diff --git a/caps/idl/nsIScriptSecurityManager.idl b/caps/idl/nsIScriptSecurityManager.idl
index 974ee77276b..c7d5e91c616 100644
--- a/caps/idl/nsIScriptSecurityManager.idl
+++ b/caps/idl/nsIScriptSecurityManager.idl
@@ -240,5 +240,4 @@ interface nsIScriptSecurityManager : nsIXPCSecurityManager
 
 %{C++
 #define NS_SCRIPTSECURITYMANAGER_CONTRACTID "@mozilla.org/scriptsecuritymanager;1"
-#define NS_SCRIPTSECURITYMANAGER_CLASSNAME "scriptsecuritymanager"
 %}
diff --git a/caps/include/nsNullPrincipal.h b/caps/include/nsNullPrincipal.h
index 79922ae6037..10b83f3cfa0 100644
--- a/caps/include/nsNullPrincipal.h
+++ b/caps/include/nsNullPrincipal.h
@@ -19,7 +19,6 @@
 
 class nsIURI;
 
-#define NS_NULLPRINCIPAL_CLASSNAME "nullprincipal"
 #define NS_NULLPRINCIPAL_CID \
 { 0xdd156d62, 0xd26f, 0x4441, \
  { 0x9c, 0xdb, 0xe8, 0xf0, 0x91, 0x07, 0xc2, 0x73 } }
diff --git a/caps/include/nsPrincipal.h b/caps/include/nsPrincipal.h
index 46c6510560c..21eb0b60687 100644
--- a/caps/include/nsPrincipal.h
+++ b/caps/include/nsPrincipal.h
@@ -166,13 +166,11 @@ private:
   nsTArray< nsCOMPtr<nsIPrincipal> > mPrincipals;
 };
 
-#define NS_PRINCIPAL_CLASSNAME  "principal"
 #define NS_PRINCIPAL_CONTRACTID "@mozilla.org/principal;1"
 #define NS_PRINCIPAL_CID \
   { 0x09b7e598, 0x490d, 0x423f, \
     { 0xa8, 0xa6, 0x2e, 0x6c, 0x4e, 0xc8, 0x77, 0x50 }}
 
-#define NS_EXPANDEDPRINCIPAL_CLASSNAME  "expandedprincipal"
 #define NS_EXPANDEDPRINCIPAL_CONTRACTID "@mozilla.org/expandedprincipal;1"
 #define NS_EXPANDEDPRINCIPAL_CID \
   { 0xb33a3807, 0xb76c, 0x44e5, \
diff --git a/caps/include/nsSystemPrincipal.h b/caps/include/nsSystemPrincipal.h
index cfbebd563ea..6c5d00525ca 100644
--- a/caps/include/nsSystemPrincipal.h
+++ b/caps/include/nsSystemPrincipal.h
@@ -11,7 +11,6 @@
 #include "nsIPrincipal.h"
 #include "nsJSPrincipals.h"
 
-#define NS_SYSTEMPRINCIPAL_CLASSNAME "systemprincipal"
 #define NS_SYSTEMPRINCIPAL_CID \
 { 0x4a6212db, 0xaccb, 0x11d3, \
 { 0xb7, 0x65, 0x0, 0x60, 0xb0, 0xb6, 0xce, 0xcb }}
diff --git a/dom/base/Crypto.h b/dom/base/Crypto.h
index 0f967c9e5c8..c22dc8ad06f 100644
--- a/dom/base/Crypto.h
+++ b/dom/base/Crypto.h
@@ -10,7 +10,6 @@
 #include "nsIDOMCryptoLegacy.h"
 #endif
 
-#define NS_DOMCRYPTO_CLASSNAME "Crypto JavaScript Class"
 #define NS_DOMCRYPTO_CID \
   {0x929d9320, 0x251e, 0x11d4, { 0x8a, 0x7c, 0x00, 0x60, 0x08, 0xc8, 0x44, 0xc3} }
 
diff --git a/dom/base/nsStructuredCloneContainer.h b/dom/base/nsStructuredCloneContainer.h
index baef6d18446..864e5716e03 100644
--- a/dom/base/nsStructuredCloneContainer.h
+++ b/dom/base/nsStructuredCloneContainer.h
@@ -12,7 +12,6 @@
 #include "jsapi.h"
 #include "mozilla/Attributes.h"
 
-#define NS_STRUCTUREDCLONECONTAINER_CLASSNAME "nsStructuredCloneContainer"
 #define NS_STRUCTUREDCLONECONTAINER_CONTRACTID \
   "@mozilla.org/docshell/structured-clone-container;1"
 #define NS_STRUCTUREDCLONECONTAINER_CID \
diff --git a/embedding/components/appstartup/src/nsIAppStartupNotifier.h b/embedding/components/appstartup/src/nsIAppStartupNotifier.h
index ff3053ffecb..113bfa17144 100644
--- a/embedding/components/appstartup/src/nsIAppStartupNotifier.h
+++ b/embedding/components/appstartup/src/nsIAppStartupNotifier.h
@@ -43,7 +43,6 @@
 */
 
 #define NS_APPSTARTUPNOTIFIER_CONTRACTID "@mozilla.org/embedcomp/appstartup-notifier;1"
-#define NS_APPSTARTUPNOTIFIER_CLASSNAME  "AppStartup Notifier"
 
 #define APPSTARTUP_CATEGORY "app-startup"
 #define APPSTARTUP_TOPIC    "app-startup"
diff --git a/extensions/pref/autoconfig/public/nsIAutoConfig.idl b/extensions/pref/autoconfig/public/nsIAutoConfig.idl
index 18aed401de8..e76dc0614c8 100644
--- a/extensions/pref/autoconfig/public/nsIAutoConfig.idl
+++ b/extensions/pref/autoconfig/public/nsIAutoConfig.idl
@@ -18,8 +18,6 @@
 #define NS_AUTOCONFIG_CONTRACTID \
   "@mozilla.org/autoconfiguration;1" 
 
-#define NS_AUTOCONFIG_CLASSNAME "AutoConfig Module"
-
 %}
 
 [uuid (80DB54AE-13F2-11d5-BE44-00108335A220)]
diff --git a/extensions/pref/autoconfig/public/nsIReadConfig.idl b/extensions/pref/autoconfig/public/nsIReadConfig.idl
index 6f5b060ae1d..e00c06e526c 100644
--- a/extensions/pref/autoconfig/public/nsIReadConfig.idl
+++ b/extensions/pref/autoconfig/public/nsIReadConfig.idl
@@ -17,8 +17,6 @@
 #define NS_READCONFIG_CONTRACTID \
   "@mozilla.org/readconfig;1" 
 
-#define NS_READCONFIG_CLASSNAME "ReadConfig Module"
-
 %}
 
 [uuid (ba5bc4c6-1dd1-11b2-bb89-b844c6ec0339)]
diff --git a/js/xpconnect/idl/nsIScriptError.idl b/js/xpconnect/idl/nsIScriptError.idl
index d609cd32cf8..74388de4a49 100644
--- a/js/xpconnect/idl/nsIScriptError.idl
+++ b/js/xpconnect/idl/nsIScriptError.idl
@@ -92,8 +92,6 @@ interface nsIScriptError : nsIConsoleMessage
 };
 
 %{ C++
-#define NS_SCRIPTERROR_CLASSNAME "Script Error"
-
 #define NS_SCRIPTERROR_CID \
 { 0xe38e53b9, 0x5bb0, 0x456a, { 0xb5, 0x53, 0x57, 0x93, 0x70, 0xcb, 0x15, 0x67 }}
 
diff --git a/modules/libjar/nsJARProtocolHandler.h b/modules/libjar/nsJARProtocolHandler.h
index 1b55f8f05bb..2270e57cef9 100644
--- a/modules/libjar/nsJARProtocolHandler.h
+++ b/modules/libjar/nsJARProtocolHandler.h
@@ -62,8 +62,6 @@ protected:
 
 extern nsJARProtocolHandler *gJarHandler;
 
-#define NS_JARPROTOCOLHANDLER_CLASSNAME \
-    "nsJarProtocolHandler"
 #define NS_JARPROTOCOLHANDLER_CID                    \
 { /* 0xc7e410d4-0x85f2-11d3-9f63-006008a6efe9 */     \
     0xc7e410d4,                                      \
diff --git a/modules/libjar/nsJARURI.h b/modules/libjar/nsJARURI.h
index 79d8eaefdef..f7d62605063 100644
--- a/modules/libjar/nsJARURI.h
+++ b/modules/libjar/nsJARURI.h
@@ -23,8 +23,6 @@
     {0xb7, 0x5b, 0xfa, 0x7d, 0x95, 0x70, 0xa6, 0x91} \
 }
 
-#define NS_JARURI_CLASSNAME \
-    "nsJARURI"
 #define NS_JARURI_CID                                \
 { /* 245abae2-b947-4ded-a46d-9829d3cca462 */         \
     0x245abae2,                                      \
diff --git a/modules/libjar/zipwriter/src/nsDeflateConverter.h b/modules/libjar/zipwriter/src/nsDeflateConverter.h
index c84da99e0b1..51c4778708d 100644
--- a/modules/libjar/zipwriter/src/nsDeflateConverter.h
+++ b/modules/libjar/zipwriter/src/nsDeflateConverter.h
@@ -12,7 +12,6 @@
 #include "zlib.h"
 #include "mozilla/Attributes.h"
 
-#define DEFLATECONVERTER_CLASSNAME "Deflate converter"
 #define DEFLATECONVERTER_CID { 0x461cd5dd, 0x73c6, 0x47a4, \
            { 0x8c, 0xc3, 0x60, 0x3b, 0x37, 0xd8, 0x4a, 0x61 } }
 
diff --git a/modules/libjar/zipwriter/src/nsZipWriter.h b/modules/libjar/zipwriter/src/nsZipWriter.h
index c63811821f9..0a35f3773e5 100644
--- a/modules/libjar/zipwriter/src/nsZipWriter.h
+++ b/modules/libjar/zipwriter/src/nsZipWriter.h
@@ -18,7 +18,6 @@
 #include "mozilla/Attributes.h"
 
 #define ZIPWRITER_CONTRACTID "@mozilla.org/zipwriter;1"
-#define ZIPWRITER_CLASSNAME "Zip Writer"
 #define ZIPWRITER_CID { 0x430d416c, 0xa722, 0x4ad1, \
            { 0xbe, 0x98, 0xd9, 0xa4, 0x45, 0xf8, 0x5e, 0x3f } }
 
diff --git a/modules/libpref/public/nsIPrefBranch.idl b/modules/libpref/public/nsIPrefBranch.idl
index 07fb494871e..22a8244f9a2 100644
--- a/modules/libpref/public/nsIPrefBranch.idl
+++ b/modules/libpref/public/nsIPrefBranch.idl
@@ -410,7 +410,6 @@ interface nsIPrefBranch : nsISupports
 %{C++
 
 #define NS_PREFBRANCH_CONTRACTID "@mozilla.org/preferencesbranch;1"
-#define NS_PREFBRANCH_CLASSNAME "Preferences Branch"
 /**
  * Notification sent when a preference changes.
  */
diff --git a/modules/libpref/public/nsIPrefLocalizedString.idl b/modules/libpref/public/nsIPrefLocalizedString.idl
index 3b0d934e5a1..935ef065665 100644
--- a/modules/libpref/public/nsIPrefLocalizedString.idl
+++ b/modules/libpref/public/nsIPrefLocalizedString.idl
@@ -63,6 +63,5 @@ interface nsIPrefLocalizedString : nsISupports
   }
 
 #define NS_PREFLOCALIZEDSTRING_CONTRACTID "@mozilla.org/pref-localizedstring;1"
-#define NS_PREFLOCALIZEDSTRING_CLASSNAME "Pref LocalizedString"
 
 %}
diff --git a/modules/libpref/public/nsIPrefService.idl b/modules/libpref/public/nsIPrefService.idl
index 735def31995..9b7c29894d5 100644
--- a/modules/libpref/public/nsIPrefService.idl
+++ b/modules/libpref/public/nsIPrefService.idl
@@ -138,7 +138,6 @@ interface nsIPrefService : nsISupports
   }
 
 #define NS_PREFSERVICE_CONTRACTID "@mozilla.org/preferences-service;1"
-#define NS_PREFSERVICE_CLASSNAME "Preferences Server"
 
 /**
  * Notification sent before reading the default user preferences files.
diff --git a/modules/libpref/public/nsIRelativeFilePref.idl b/modules/libpref/public/nsIRelativeFilePref.idl
index 9c695533760..4b86e375583 100644
--- a/modules/libpref/public/nsIRelativeFilePref.idl
+++ b/modules/libpref/public/nsIRelativeFilePref.idl
@@ -48,7 +48,6 @@ interface nsIRelativeFilePref : nsISupports
   }
 
 #define NS_RELATIVEFILEPREF_CONTRACTID "@mozilla.org/pref-relativefile;1"
-#define NS_RELATIVEFILEPREF_CLASSNAME "Relative File Pref"
 
 #include "nsComponentManagerUtils.h"
 
diff --git a/netwerk/base/public/nsICryptoFIPSInfo.idl b/netwerk/base/public/nsICryptoFIPSInfo.idl
index 0ac64ddb511..1defc56abc0 100644
--- a/netwerk/base/public/nsICryptoFIPSInfo.idl
+++ b/netwerk/base/public/nsICryptoFIPSInfo.idl
@@ -12,5 +12,4 @@ interface nsICryptoFIPSInfo : nsISupports
 
 %{C++
 #define NS_CRYPTO_FIPSINFO_SERVICE_CONTRACTID "@mozilla.org/crypto/fips-info-service;1"
-#define NS_CRYPTO_FIPSINFO_SERVICE_CLASSNAME "Mozilla Crypto FIPS Info Service"
 %}
diff --git a/netwerk/base/public/nsISecureBrowserUI.idl b/netwerk/base/public/nsISecureBrowserUI.idl
index 8381ae63bab..b04a0e719e8 100644
--- a/netwerk/base/public/nsISecureBrowserUI.idl
+++ b/netwerk/base/public/nsISecureBrowserUI.idl
@@ -20,5 +20,4 @@ interface nsISecureBrowserUI : nsISupports
 
 %{C++
 #define NS_SECURE_BROWSER_UI_CONTRACTID "@mozilla.org/secure_browser_ui;1"
-#define NS_SECURE_BROWSER_UI_CLASSNAME "Mozilla Secure Browser UI Handler"
 %}
diff --git a/netwerk/base/public/nsIStrictTransportSecurityService.idl b/netwerk/base/public/nsIStrictTransportSecurityService.idl
index d7ea728f1c6..386f708ad94 100644
--- a/netwerk/base/public/nsIStrictTransportSecurityService.idl
+++ b/netwerk/base/public/nsIStrictTransportSecurityService.idl
@@ -81,7 +81,6 @@ interface nsIStrictTransportSecurityService : nsISupports
 
 %{C++
 #define NS_STSSERVICE_CONTRACTID "@mozilla.org/stsservice;1"
-#define NS_STSSERVICE_CLASSNAME "stsservice"
 
 #define STS_PERMISSION "sts/use"
 #define STS_SUBDOMAIN_PERMISSION "sts/subd"
diff --git a/netwerk/base/src/nsMIMEInputStream.h b/netwerk/base/src/nsMIMEInputStream.h
index fbe17f9bbb0..38823d7ae46 100644
--- a/netwerk/base/src/nsMIMEInputStream.h
+++ b/netwerk/base/src/nsMIMEInputStream.h
@@ -13,7 +13,6 @@
 
 #include "nsIMIMEInputStream.h"
 
-#define NS_MIMEINPUTSTREAM_CLASSNAME  "nsMIMEInputStream"
 #define NS_MIMEINPUTSTREAM_CONTRACTID "@mozilla.org/network/mime-input-stream;1"
 #define NS_MIMEINPUTSTREAM_CID                       \
 { /* 58a1c31c-1dd2-11b2-a3f6-d36949d48268 */         \
diff --git a/netwerk/build/nsNetCID.h b/netwerk/build/nsNetCID.h
index b9245907f1b..cc5a4caed96 100644
--- a/netwerk/build/nsNetCID.h
+++ b/netwerk/build/nsNetCID.h
@@ -12,8 +12,6 @@
  */
 
 // service implementing nsIIOService and nsIIOService2.
-#define NS_IOSERVICE_CLASSNAME \
-    "nsIOService"
 #define NS_IOSERVICE_CONTRACTID \
     "@mozilla.org/network/io-service;1"
 #define NS_IOSERVICE_CID                             \
@@ -29,8 +27,6 @@
     "@mozilla.org/network/util;1"
 
 // serialization scriptable helper
-#define NS_SERIALIZATION_HELPER_CLASSNAME \
-  "nsSerializationHelper"
 #define NS_SERIALIZATION_HELPER_CONTRACTID \
   "@mozilla.org/network/serialization-helper;1"
 #define NS_SERIALIZATION_HELPER_CID                  \
@@ -42,8 +38,6 @@
 }
 
 // service implementing nsIProtocolProxyService and nsPIProtocolProxyService.
-#define NS_PROTOCOLPROXYSERVICE_CLASSNAME \
-    "nsProtocolProxyService"
 #define NS_PROTOCOLPROXYSERVICE_CONTRACTID \
     "@mozilla.org/network/protocol-proxy-service;1"
 #define NS_PROTOCOLPROXYSERVICE_CID                  \
@@ -55,8 +49,6 @@
 }
 
 // service implementing nsIProxyAutoConfig.
-#define NS_PROXYAUTOCONFIG_CLASSNAME \
-    "nsProxyAutoConfig"
 #define NS_PROXYAUTOCONFIG_CONTRACTID \
     "@mozilla.org/network/proxy-auto-config;1" 
 #define NS_PROXYAUTOCONFIG_CID                       \
@@ -68,8 +60,6 @@
 }
 
 // component implementing nsILoadGroup.
-#define NS_LOADGROUP_CLASSNAME \
-    "nsLoadGroup"
 #define NS_LOADGROUP_CONTRACTID \
     "@mozilla.org/network/load-group;1"
 #define NS_LOADGROUP_CID                             \
@@ -81,8 +71,6 @@
 }
 
 // component implementing nsIURI, nsISerializable, and nsIClassInfo.
-#define NS_SIMPLEURI_CLASSNAME \
-    "nsSimpleURI"
 #define NS_SIMPLEURI_CONTRACTID \
     "@mozilla.org/network/simple-uri;1"
 #define NS_SIMPLEURI_CID                              \
@@ -115,8 +103,6 @@
 
 // component implementing nsIStandardURL, nsIURI, nsIURL, nsISerializable,
 // and nsIClassInfo.
-#define NS_STANDARDURL_CLASSNAME \
-    "nsStandardURL"
 #define NS_STANDARDURL_CONTRACTID \
     "@mozilla.org/network/standard-url;1"
 #define NS_STANDARDURL_CID                           \
@@ -129,8 +115,6 @@
 
 // service implementing nsIURLParser that assumes the URL will NOT contain an
 // authority section.
-#define NS_NOAUTHURLPARSER_CLASSNAME \
-    "nsNoAuthURLParser"
 #define NS_NOAUTHURLPARSER_CONTRACTID \
     "@mozilla.org/network/url-parser;1?auth=no"
 #define NS_NOAUTHURLPARSER_CID                       \
@@ -143,8 +127,6 @@
 
 // service implementing nsIURLParser that assumes the URL will contain an
 // authority section.
-#define NS_AUTHURLPARSER_CLASSNAME \
-    "nsAuthURLParser"
 #define NS_AUTHURLPARSER_CONTRACTID \
     "@mozilla.org/network/url-parser;1?auth=yes"
 #define NS_AUTHURLPARSER_CID                         \
@@ -157,8 +139,6 @@
 
 // service implementing nsIURLParser that does not make any assumptions about
 // whether or not the URL contains an authority section.
-#define NS_STDURLPARSER_CLASSNAME \
-    "nsStdURLParser"
 #define NS_STDURLPARSER_CONTRACTID \
     "@mozilla.org/network/url-parser;1?auth=maybe"
 #define NS_STDURLPARSER_CID                          \
@@ -170,8 +150,6 @@
 }
 
 // component implementing nsIRequestObserverProxy.
-#define NS_REQUESTOBSERVERPROXY_CLASSNAME \
-    "nsRequestObserverProxy"
 #define NS_REQUESTOBSERVERPROXY_CONTRACTID \
     "@mozilla.org/network/request-observer-proxy;1"
 #define NS_REQUESTOBSERVERPROXY_CID                  \
@@ -183,8 +161,6 @@
 }
 
 // component implementing nsISimpleStreamListener.
-#define NS_SIMPLESTREAMLISTENER_CLASSNAME \
-    "nsSimpleStreamListener"
 #define NS_SIMPLESTREAMLISTENER_CONTRACTID \
     "@mozilla.org/network/simple-stream-listener;1"
 #define NS_SIMPLESTREAMLISTENER_CID                  \
@@ -196,8 +172,6 @@
 }
 
 // component implementing nsIStreamListenerTee.
-#define NS_STREAMLISTENERTEE_CLASSNAME \
-    "nsStreamListenerTee"
 #define NS_STREAMLISTENERTEE_CONTRACTID \
     "@mozilla.org/network/stream-listener-tee;1"
 #define NS_STREAMLISTENERTEE_CID                     \
@@ -209,8 +183,6 @@
 }
 
 // component implementing nsIAsyncStreamCopier.
-#define NS_ASYNCSTREAMCOPIER_CLASSNAME \
-    "nsAsyncStreamCopier"
 #define NS_ASYNCSTREAMCOPIER_CONTRACTID \
     "@mozilla.org/network/async-stream-copier;1"
 #define NS_ASYNCSTREAMCOPIER_CID                     \
@@ -222,8 +194,6 @@
 }
 
 // component implementing nsIInputStreamPump.
-#define NS_INPUTSTREAMPUMP_CLASSNAME \
-    "nsInputStreamPump"
 #define NS_INPUTSTREAMPUMP_CONTRACTID \
     "@mozilla.org/network/input-stream-pump;1"
 #define NS_INPUTSTREAMPUMP_CID                       \
@@ -235,8 +205,6 @@
 }
 
 // component implementing nsIInputStreamChannel.
-#define NS_INPUTSTREAMCHANNEL_CLASSNAME \
-    "nsInputStreamChannel"
 #define NS_INPUTSTREAMCHANNEL_CONTRACTID \
     "@mozilla.org/network/input-stream-channel;1"
 #define NS_INPUTSTREAMCHANNEL_CID                    \
@@ -248,8 +216,6 @@
 }
 
 // component implementing nsIStreamLoader.
-#define NS_STREAMLOADER_CLASSNAME \
-    "nsStreamLoader"
 #define NS_STREAMLOADER_CONTRACTID \
     "@mozilla.org/network/stream-loader;1"
 #define NS_STREAMLOADER_CID \
@@ -261,8 +227,6 @@
 }
 
 // component implementing nsIUnicharStreamLoader.
-#define NS_UNICHARSTREAMLOADER_CLASSNAME \
-    "nsUnicharStreamLoader"
 #define NS_UNICHARSTREAMLOADER_CONTRACTID \
     "@mozilla.org/network/unichar-stream-loader;1"
 #define NS_UNICHARSTREAMLOADER_CID \
@@ -274,8 +238,6 @@
 }
 
 // component implementing nsIDownloader.
-#define NS_DOWNLOADER_CLASSNAME \
-    "nsDownloader"
 #define NS_DOWNLOADER_CONTRACTID \
     "@mozilla.org/network/downloader;1"
 #define NS_DOWNLOADER_CID \
@@ -288,8 +250,6 @@
 
 // component implementing nsIBackgroundFileSaver and
 // nsIOutputStream.
-#define NS_BACKGROUNDFILESAVEROUTPUTSTREAM_CLASSNAME \
-    "BackgroundFileSaverOutputStream"
 #define NS_BACKGROUNDFILESAVEROUTPUTSTREAM_CONTRACTID \
     "@mozilla.org/network/background-file-saver;1?mode=outputstream"
 #define NS_BACKGROUNDFILESAVEROUTPUTSTREAM_CID \
@@ -302,8 +262,6 @@
 
 // component implementing nsIBackgroundFileSaver and
 // nsIStreamListener.
-#define NS_BACKGROUNDFILESAVERSTREAMLISTENER_CLASSNAME \
-    "BackgroundFileSaverStreamListener"
 #define NS_BACKGROUNDFILESAVERSTREAMLISTENER_CONTRACTID \
     "@mozilla.org/network/background-file-saver;1?mode=streamlistener"
 #define NS_BACKGROUNDFILESAVERSTREAMLISTENER_CID \
@@ -315,8 +273,6 @@
 }
 
 // component implementing nsISyncStreamListener.
-#define NS_SYNCSTREAMLISTENER_CLASSNAME \
-    "nsSyncStreamListener"
 #define NS_SYNCSTREAMLISTENER_CONTRACTID \
     "@mozilla.org/network/sync-stream-listener;1"
 #define NS_SYNCSTREAMLISTENER_CID \
@@ -328,8 +284,6 @@
 }
 
 // component implementing nsIURIChecker.
-#define NS_URICHECKER_CLASSNAME \
-    "nsURIChecker"
 #define NS_URICHECKER_CONTRACT_ID \
     "@mozilla.org/network/urichecker;1"
 #define NS_URICHECKER_CID \
@@ -349,8 +303,6 @@
     "@mozilla.org/system-proxy-settings;1"
 
 // service implementing nsIStreamTransportService
-#define NS_STREAMTRANSPORTSERVICE_CLASSNAME \
-    "nsStreamTransportService"
 #define NS_STREAMTRANSPORTSERVICE_CONTRACTID \
     "@mozilla.org/network/stream-transport-service;1"
 #define NS_STREAMTRANSPORTSERVICE_CID \
@@ -362,8 +314,6 @@
 }
 
 // service implementing nsISocketTransportService
-#define NS_SOCKETTRANSPORTSERVICE_CLASSNAME \
-    "nsSocketTransportService"
 #define NS_SOCKETTRANSPORTSERVICE_CONTRACTID \
     "@mozilla.org/network/socket-transport-service;1"
 #define NS_SOCKETTRANSPORTSERVICE_CID                \
@@ -375,8 +325,6 @@
 }
 
 // component implementing nsIServerSocket
-#define NS_SERVERSOCKET_CLASSNAME \
-    "nsServerSocket"
 #define NS_SERVERSOCKET_CONTRACTID \
     "@mozilla.org/network/server-socket;1"
 #define NS_SERVERSOCKET_CID                          \
@@ -388,8 +336,6 @@
 }
 
 // component implementing nsIUDPServerSocket
-#define NS_UDPSERVERSOCKET_CLASSNAME \
-    "nsUDPServerSocket"
 #define NS_UDPSERVERSOCKET_CONTRACTID \
     "@mozilla.org/network/server-socket-udp;1"
 #define NS_UDPSERVERSOCKET_CID                       \
@@ -400,8 +346,6 @@
     {0xbb, 0x4a, 0x03, 0xc0, 0xd3, 0x02, 0x1b, 0xd6} \
 }
 
-#define NS_LOCALFILEINPUTSTREAM_CLASSNAME \
-    "nsFileInputStream"
 #define NS_LOCALFILEINPUTSTREAM_CONTRACTID \
     "@mozilla.org/network/file-input-stream;1"
 #define NS_LOCALFILEINPUTSTREAM_CID                  \
@@ -412,8 +356,6 @@
     {0x8c, 0xda, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
 }
 
-#define NS_LOCALFILEOUTPUTSTREAM_CLASSNAME \
-    "nsFileOutputStream"
 #define NS_LOCALFILEOUTPUTSTREAM_CONTRACTID \
     "@mozilla.org/network/file-output-stream;1"
 #define NS_LOCALFILEOUTPUTSTREAM_CID                 \
@@ -424,8 +366,6 @@
     {0x8c, 0xda, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
 }
 
-#define NS_PARTIALLOCALFILEINPUTSTREAM_CLASSNAME \
-    "nsPartialFileInputStream"
 #define NS_PARTIALLOCALFILEINPUTSTREAM_CONTRACTID \
     "@mozilla.org/network/partial-file-input-stream;1"
 #define NS_PARTIALLOCALFILEINPUTSTREAM_CID           \
@@ -436,8 +376,6 @@
     {0xa9, 0x9b, 0x75, 0xb3, 0xa6, 0xb1, 0x0a, 0x56} \
 }
 
-#define NS_BUFFEREDINPUTSTREAM_CLASSNAME \
-    "nsBufferedInputStream"
 #define NS_BUFFEREDINPUTSTREAM_CONTRACTID \
     "@mozilla.org/network/buffered-input-stream;1"
 #define NS_BUFFEREDINPUTSTREAM_CID                   \
@@ -448,8 +386,6 @@
     {0x8c, 0xda, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
 }
 
-#define NS_BUFFEREDOUTPUTSTREAM_CLASSNAME \
-    "nsBufferedOutputStream"
 #define NS_BUFFEREDOUTPUTSTREAM_CONTRACTID \
     "@mozilla.org/network/buffered-output-stream;1"
 #define NS_BUFFEREDOUTPUTSTREAM_CID                  \
@@ -461,8 +397,6 @@
 }
 
 // component implementing nsISafeOutputStream
-#define NS_SAFELOCALFILEOUTPUTSTREAM_CLASSNAME \
-    "nsSafeFileOutputStream"
 #define NS_SAFELOCALFILEOUTPUTSTREAM_CONTRACTID \
     "@mozilla.org/network/safe-file-output-stream;1"
 #define NS_SAFELOCALFILEOUTPUTSTREAM_CID             \
@@ -474,8 +408,6 @@
 }
 
 // component implementing nsIFileStream
-#define NS_LOCALFILESTREAM_CLASSNAME \
-    "nsFileStream"
 #define NS_LOCALFILESTREAM_CONTRACTID \
     "@mozilla.org/network/file-stream;1"
 #define NS_LOCALFILESTREAM_CID                       \
@@ -509,8 +441,6 @@
  */
 
 // service implementing nsICacheService.
-#define NS_CACHESERVICE_CLASSNAME \
-    "nsCacheService"
 #define NS_CACHESERVICE_CONTRACTID \
     "@mozilla.org/network/cache-service;1"
 #define NS_CACHESERVICE_CID                          \
@@ -522,8 +452,6 @@
 }
 
 // service implementing nsIApplicationCacheService.
-#define NS_APPLICATIONCACHESERVICE_CLASSNAME \
-    "nsApplicationCacheService"
 #define NS_APPLICATIONCACHESERVICE_CONTRACTID \
     "@mozilla.org/network/application-cache-service;1"
 #define NS_APPLICATIONCACHESERVICE_CID               \
@@ -534,8 +462,6 @@
     {0xa5, 0x0c, 0x2c, 0xbb, 0x08, 0x5a, 0xb7, 0xa5} \
 }
 
-#define NS_APPLICATIONCACHENAMESPACE_CLASSNAME \
-    "nsApplicationCacheNamespace"
 #define NS_APPLICATIONCACHENAMESPACE_CONTRACTID \
     "@mozilla.org/network/application-cache-namespace;1"
 #define NS_APPLICATIONCACHENAMESPACE_CID             \
@@ -546,8 +472,6 @@
    {0x8e, 0x1c, 0xd1, 0xaf, 0x79, 0xdf, 0xd1, 0x2f}  \
 }
 
-#define NS_APPLICATIONCACHE_CLASSNAME \
-    "nsApplicationCache"
 #define NS_APPLICATIONCACHE_CONTRACTID \
     "@mozilla.org/network/application-cache;1"
 
@@ -603,8 +527,6 @@
     {0xb5, 0x3e, 0xe6, 0x1e, 0x74, 0xc2, 0x45, 0x1a} \
 }
 
-#define NS_HTTPAUTHMANAGER_CLASSNAME \
-    "nsHttpAuthManager"
 #define NS_HTTPAUTHMANAGER_CONTRACTID \
     "@mozilla.org/network/http-auth-manager;1"
 #define NS_HTTPAUTHMANAGER_CID \
@@ -615,8 +537,6 @@
     {0x9f, 0xd4, 0xe0, 0x65, 0xe8, 0x55, 0x68, 0xf4} \
 }
 
-#define NS_HTTPCHANNELAUTHPROVIDER_CLASSNAME \
-    "nsHttpChannelAuthProvider"
 #define NS_HTTPCHANNELAUTHPROVIDER_CONTRACTID \
     "@mozilla.org/network/http-channel-auth-provider;1"
 #define NS_HTTPCHANNELAUTHPROVIDER_CID \
@@ -627,8 +547,6 @@
     {0xb5, 0x27, 0x8a, 0x64, 0x30, 0x56, 0xab, 0xbd} \
 }
 
-#define NS_HTTPACTIVITYDISTRIBUTOR_CLASSNAME \
-    "nsHttpActivityDistributor"
 #define NS_HTTPACTIVITYDISTRIBUTOR_CONTRACTID \
     "@mozilla.org/network/http-activity-distributor;1"
 #define NS_HTTPACTIVITYDISTRIBUTOR_CID \
@@ -643,8 +561,6 @@
  * netwerk/protocol/ftp/ classes
  */
 
-#define NS_FTPPROTOCOLHANDLER_CLASSNAME \
-    "nsFtpProtocolHandler"
 #define NS_FTPPROTOCOLHANDLER_CID \
 { /* 25029490-F132-11d2-9588-00805F369F95 */         \
     0x25029490,                                      \
@@ -657,8 +573,6 @@
  * netwerk/protocol/res/ classes
  */
 
-#define NS_RESPROTOCOLHANDLER_CLASSNAME \
-    "nsResProtocolHandler"
 #define NS_RESPROTOCOLHANDLER_CID                    \
 { /* e64f152a-9f07-11d3-8cda-0060b0fc14a3 */         \
     0xe64f152a,                                      \
@@ -667,8 +581,6 @@
     {0x8c, 0xda, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
 }
 
-#define NS_RESURL_CLASSNAME \
-    "nsResURL"
 #define NS_RESURL_CID                    \
 { /* ff8fe7ec-2f74-4408-b742-6b7a546029a8 */         \
     0xff8fe7ec,                                      \
@@ -682,8 +594,6 @@
  * netwerk/protocol/file/ classes
  */
 
-#define NS_FILEPROTOCOLHANDLER_CLASSNAME \
-    "nsFileProtocolHandler"
 #define NS_FILEPROTOCOLHANDLER_CID                   \
 { /* fbc81170-1f69-11d3-9344-00104ba0fd40 */         \
     0xfbc81170,                                      \
@@ -696,8 +606,6 @@
  * netwerk/protocol/data/ classes
  */
 
-#define NS_DATAPROTOCOLHANDLER_CLASSNAME \
-    "nsDataProtocolHandler"
 #define NS_DATAPROTOCOLHANDLER_CID                   \
 { /* {B6ED3030-6183-11d3-A178-0050041CAF44} */       \
     0xb6ed3030,                                      \
@@ -709,8 +617,6 @@
 /******************************************************************************
  * netwerk/protocol/device classes
  */
-#define NS_DEVICEPROTOCOLHANDLER_CLASSNAME \
-    "nsDeviceProtocolHandler"
 #define NS_DEVICEPROTOCOLHANDLER_CID                 \
 { /* 6b0ffe9e-d114-486b-aeb7-da62e7273ed5 */         \
     0x60ffe9e,                                       \
@@ -768,8 +674,6 @@
  * netwerk/protocol/about/ classes
  */
 
-#define NS_ABOUTPROTOCOLHANDLER_CLASSNAME \
-    "About Protocol Handler"
 #define NS_ABOUTPROTOCOLHANDLER_CID                  \
 { /* 9e3b6c90-2f75-11d3-8cd0-0060b0fc14a3 */         \
     0x9e3b6c90,                                      \
@@ -778,8 +682,6 @@
     {0x8c, 0xd0, 0x00, 0x60, 0xb0, 0xfc, 0x14, 0xa3} \
 }
 
-#define NS_SAFEABOUTPROTOCOLHANDLER_CLASSNAME \
-    "Safe About Protocol Handler"
 #define NS_SAFEABOUTPROTOCOLHANDLER_CID              \
 { /* 1423e739-782c-4081-b5d8-fe6fba68c0ef */         \
     0x1423e739,                                      \
@@ -792,8 +694,6 @@
  * netwerk/dns/ classes
  */
 
-#define NS_DNSSERVICE_CLASSNAME \
-    "nsDNSService"
 #define NS_DNSSERVICE_CONTRACTID \
     "@mozilla.org/network/dns-service;1"
 #define NS_DNSSERVICE_CID \
@@ -804,8 +704,6 @@
     {0xa0, 0x92, 0x83, 0xc1, 0xb8, 0x8f, 0x6b, 0xe9} \
 }
 
-#define NS_IDNSERVICE_CLASSNAME \
-    "nsIDNService"
 /* ContractID of the XPCOM package that implements nsIIDNService */
 #define NS_IDNSERVICE_CONTRACTID \
     "@mozilla.org/network/idn-service;1"
@@ -817,8 +715,6 @@
     {0x8c, 0x31, 0x28, 0x65, 0xfb, 0xb6, 0x8c, 0x91} \
 }
 
-#define NS_EFFECTIVETLDSERVICE_CLASSNAME \
-    "nsEffectiveTLDService"
 #define NS_EFFECTIVETLDSERVICE_CONTRACTID \
     "@mozilla.org/network/effective-tld-service;1"
 #define NS_EFFECTIVETLDSERVICE_CID \
@@ -834,8 +730,6 @@
  * netwerk/mime classes
  */
 
-#define NS_MIMEHEADERPARAM_CLASSNAME \
-    "nsMIMEHeaderParamImpl"
 // {1F4DBCF7-245C-4c8c-943D-8A1DA0495E8A} 
 #define NS_MIMEHEADERPARAM_CID                         \
 {   0x1f4dbcf7,                                        \
@@ -851,8 +745,6 @@
  * netwerk/socket classes
  */
 
-#define NS_SOCKETPROVIDERSERVICE_CLASSNAME \
-    "nsSocketProviderService"
 #define NS_SOCKETPROVIDERSERVICE_CONTRACTID \
     "@mozilla.org/network/socket-provider-service;1"
 #define NS_SOCKETPROVIDERSERVICE_CID                   \
@@ -897,8 +789,6 @@
     NS_NETWORK_SOCKET_CONTRACTID_PREFIX "starttls"
 
 
-#define NS_DASHBOARD_CLASSNAME \
-    "Dashboard"
 #define NS_DASHBOARD_CONTRACTID \
     "@mozilla.org/network/dashboard;1"
 #define NS_DASHBOARD_CID                               \
@@ -915,8 +805,6 @@
  */
 
 // service implementing nsICookieManager and nsICookieManager2.
-#define NS_COOKIEMANAGER_CLASSNAME \
-    "CookieManager"
 #define NS_COOKIEMANAGER_CONTRACTID \
     "@mozilla.org/cookiemanager;1"
 #define NS_COOKIEMANAGER_CID                           \
@@ -928,8 +816,6 @@
 }
 
 // service implementing nsICookieService.
-#define NS_COOKIESERVICE_CLASSNAME \
-    "CookieService"
 #define NS_COOKIESERVICE_CONTRACTID \
     "@mozilla.org/cookieService;1"
 #define NS_COOKIESERVICE_CID                           \
@@ -944,7 +830,6 @@
  * netwerk/wifi classes
  */
 #ifdef NECKO_WIFI
-#define NS_WIFI_MONITOR_CLASSNAME  "WIFI_MONITOR"
 #define NS_WIFI_MONITOR_CONTRACTID "@mozilla.org/wifi/monitor;1"
 
 #define NS_WIFI_MONITOR_COMPONENT_CID                  \
@@ -991,7 +876,6 @@
  */
 
 // service implementing nsINetworkLinkService
-#define NS_NETWORK_LINK_SERVICE_CLASSNAME "Network Link Status"
 #define NS_NETWORK_LINK_SERVICE_CID    \
   { 0x75a500a2,                                        \
     0x0030,                                            \
diff --git a/netwerk/build/nsNetModule.cpp b/netwerk/build/nsNetModule.cpp
index fe1972567ca..96df0c652c6 100644
--- a/netwerk/build/nsNetModule.cpp
+++ b/netwerk/build/nsNetModule.cpp
@@ -124,8 +124,6 @@ NS_GENERIC_FACTORY_CONSTRUCTOR(RedirectChannelRegistrar)
 extern nsresult
 net_NewIncrementalDownload(nsISupports *, const nsIID &, void **);
 
-#define NS_INCREMENTALDOWNLOAD_CLASSNAME \
-    "nsIncrementalDownload"
 #define NS_INCREMENTALDOWNLOAD_CID \
 { /* a62af1ba-79b3-4896-8aaf-b148bfce4280 */         \
     0xa62af1ba,                                      \
diff --git a/netwerk/streamconv/public/nsIAppleFileDecoder.idl b/netwerk/streamconv/public/nsIAppleFileDecoder.idl
index cc713c58959..cc79c3d99b5 100644
--- a/netwerk/streamconv/public/nsIAppleFileDecoder.idl
+++ b/netwerk/streamconv/public/nsIAppleFileDecoder.idl
@@ -8,8 +8,6 @@
 
 
 %{C++
-#define NS_APPLEFILEDECODER_CLASSNAME    "Apple Single/Double File decoder"
-
 #define NS_APPLEFILEDECODER_CID                      \
 { /* 3a2bb281-64b8-11d5-9daa-bb433143c53c */         \
     0x3a2bb281,                                      \
diff --git a/parser/xml/src/nsSAXAttributes.h b/parser/xml/src/nsSAXAttributes.h
index e8367425b00..b859470380a 100644
--- a/parser/xml/src/nsSAXAttributes.h
+++ b/parser/xml/src/nsSAXAttributes.h
@@ -14,7 +14,6 @@
 #include "mozilla/Attributes.h"
 
 #define NS_SAXATTRIBUTES_CONTRACTID "@mozilla.org/saxparser/attributes;1"
-#define NS_SAXATTRIBUTES_CLASSNAME "SAX Attributes"
 #define NS_SAXATTRIBUTES_CID  \
 {/* {7bb40992-77eb-43db-9a4e-39d3bcc483ae}*/ \
 0x7bb40992, 0x77eb, 0x43db, \
diff --git a/parser/xml/src/nsSAXLocator.h b/parser/xml/src/nsSAXLocator.h
index 7546289d813..77d3b5cb675 100644
--- a/parser/xml/src/nsSAXLocator.h
+++ b/parser/xml/src/nsSAXLocator.h
@@ -11,7 +11,6 @@
 #include "mozilla/Attributes.h"
 
 #define NS_SAXLOCATOR_CONTRACTID "@mozilla.org/saxparser/locator;1"
-#define NS_SAXLOCATOR_CLASSNAME "SAX Locator"
 #define NS_SAXLOCATOR_CID  \
 {/* {c1cd4045-846b-43bb-a95e-745a3d7b40e0}*/ \
 0xc1cd4045, 0x846b, 0x43bb, \
diff --git a/parser/xml/src/nsSAXXMLReader.h b/parser/xml/src/nsSAXXMLReader.h
index 7715c426d9e..44ade151997 100644
--- a/parser/xml/src/nsSAXXMLReader.h
+++ b/parser/xml/src/nsSAXXMLReader.h
@@ -21,7 +21,6 @@
 #include "mozilla/Attributes.h"
 
 #define NS_SAXXMLREADER_CONTRACTID "@mozilla.org/saxparser/xmlreader;1"
-#define NS_SAXXMLREADER_CLASSNAME "SAX XML Reader"
 #define NS_SAXXMLREADER_CID  \
 { 0xab1da296, 0x6125, 0x40ba, \
 { 0x96, 0xd0, 0x47, 0xa8, 0x28, 0x2a, 0xe3, 0xdb} }
diff --git a/security/manager/ssl/public/nsIUserCertPicker.idl b/security/manager/ssl/public/nsIUserCertPicker.idl
index c802531bad0..50ae2a929dd 100644
--- a/security/manager/ssl/public/nsIUserCertPicker.idl
+++ b/security/manager/ssl/public/nsIUserCertPicker.idl
@@ -20,5 +20,4 @@ interface nsIUserCertPicker : nsISupports {
 
 %{C++
 #define NS_CERT_PICKER_CONTRACTID "@mozilla.org/user_cert_picker;1"
-#define NS_CERT_PICKER_CLASSNAME "Cert Picker Object"
 %}
diff --git a/security/manager/ssl/src/nsCMS.h b/security/manager/ssl/src/nsCMS.h
index 24f368d6e97..0e3db1de139 100644
--- a/security/manager/ssl/src/nsCMS.h
+++ b/security/manager/ssl/src/nsCMS.h
@@ -20,7 +20,6 @@
 #include "cms.h"
 #include "nsNSSShutDown.h"
 
-#define NS_CMSMESSAGE_CLASSNAME "CMS Message Object"
 #define NS_CMSMESSAGE_CID \
   { 0xa4557478, 0xae16, 0x11d5, { 0xba,0x4b,0x00,0x10,0x83,0x03,0xb1,0x17 } }
 
@@ -58,7 +57,6 @@ friend class nsSMimeVerificationJob;
 // nsCMSDecoder - implementation of nsICMSDecoder
 // ===============================================
 
-#define NS_CMSDECODER_CLASSNAME "CMS Decoder Object"
 #define NS_CMSDECODER_CID \
   { 0x9dcef3a4, 0xa3bc, 0x11d5, { 0xba, 0x47, 0x00, 0x10, 0x83, 0x03, 0xb1, 0x17 } }
 
@@ -83,7 +81,6 @@ private:
 // nsCMSEncoder - implementation of nsICMSEncoder
 // ===============================================
 
-#define NS_CMSENCODER_CLASSNAME "CMS Decoder Object"
 #define NS_CMSENCODER_CID \
   { 0xa15789aa, 0x8903, 0x462b, { 0x81, 0xe9, 0x4a, 0xa2, 0xcf, 0xf4, 0xd5, 0xcb } }
 class nsCMSEncoder : public nsICMSEncoder,
diff --git a/security/manager/ssl/src/nsCMSSecureMessage.h b/security/manager/ssl/src/nsCMSSecureMessage.h
index 8e614534040..58f41f36390 100644
--- a/security/manager/ssl/src/nsCMSSecureMessage.h
+++ b/security/manager/ssl/src/nsCMSSecureMessage.h
@@ -14,7 +14,6 @@
 // nsCMSManager - implementation of nsICMSManager
 // ===============================================
 
-#define NS_CMSSECUREMESSAGE_CLASSNAME "CMS Secure Message"
 #define NS_CMSSECUREMESSAGE_CID \
   { 0x5fb907e0, 0x1dd2, 0x11b2, { 0xa7, 0xc0, 0xf1, 0x4c, 0x41, 0x6a, 0x62, 0xa1 } }
 
diff --git a/security/manager/ssl/src/nsCrypto.h b/security/manager/ssl/src/nsCrypto.h
index 648e88b1051..f4cab7192bc 100644
--- a/security/manager/ssl/src/nsCrypto.h
+++ b/security/manager/ssl/src/nsCrypto.h
@@ -16,7 +16,6 @@
 #include "jsapi.h"
 #include "nsIPrincipal.h"
 
-#define NS_CRYPTO_CLASSNAME "Crypto JavaScript Class"
 #define NS_CRYPTO_CID \
   {0x929d9320, 0x251e, 0x11d4, { 0x8a, 0x7c, 0x00, 0x60, 0x08, 0xc8, 0x44, 0xc3} }
 #define PSM_VERSION_STRING "2.4"
@@ -64,7 +63,6 @@ private:
 
 #include "nsIPKCS11.h"
 
-#define NS_PKCS11_CLASSNAME "Pkcs11 JavaScript Class"
 #define NS_PKCS11_CID \
   {0x74b7a390, 0x3b41, 0x11d4, { 0x8a, 0x80, 0x00, 0x60, 0x08, 0xc8, 0x44, 0xc3} }
 
diff --git a/security/manager/ssl/src/nsKeyModule.h b/security/manager/ssl/src/nsKeyModule.h
index 7eb16edc4b0..d301382b781 100644
--- a/security/manager/ssl/src/nsKeyModule.h
+++ b/security/manager/ssl/src/nsKeyModule.h
@@ -9,13 +9,11 @@
 #include "pk11pub.h"
 #include "mozilla/Attributes.h"
 
-#define NS_KEYMODULEOBJECT_CLASSNAME "Key Object Component"
 /* eae599aa-ecef-49c6-a8af-6ddcc6feb484 */
 #define NS_KEYMODULEOBJECT_CID   \
 { 0xeae599aa, 0xecef, 0x49c6, {0xa8, 0xaf, 0x6d, 0xdc, 0xc6, 0xfe, 0xb4, 0x84} }
 #define NS_KEYMODULEOBJECT_CONTRACTID "@mozilla.org/security/keyobject;1"
 
-#define NS_KEYMODULEOBJECTFACTORY_CLASSNAME "Key Object Factory Component"
 /* a39e0e9d-e567-41e3-b12c-5df67f18174d */
 #define NS_KEYMODULEOBJECTFACTORY_CID   \
 { 0xa39e0e9d, 0xe567, 0x41e3, {0xb1, 0x2c, 0x5d, 0xf6, 0x7f, 0x18, 0x17, 0x4d} }
diff --git a/security/manager/ssl/src/nsNSSComponent.h b/security/manager/ssl/src/nsNSSComponent.h
index 2109244c079..37eab89a38f 100644
--- a/security/manager/ssl/src/nsNSSComponent.h
+++ b/security/manager/ssl/src/nsNSSComponent.h
@@ -43,7 +43,6 @@
 {0xa277189c, 0x1dd1, 0x11b2, {0xa8, 0xc9, 0xe4, 0xe8, 0xbf, 0xb1, 0x33, 0x8e}}
 
 #define PSM_COMPONENT_CONTRACTID "@mozilla.org/psm;1"
-#define PSM_COMPONENT_CLASSNAME "Mozilla PSM Component"
 
 //Define an interface that we can use to look up from the
 //callbacks passed to NSS.
@@ -55,11 +54,7 @@
 
 #define NS_PSMCONTENTLISTEN_CID {0xc94f4a30, 0x64d7, 0x11d4, {0x99, 0x60, 0x00, 0xb0, 0xd0, 0x23, 0x54, 0xa0}}
 #define NS_PSMCONTENTLISTEN_CONTRACTID "@mozilla.org/security/psmdownload;1"
-
-#define NS_CRYPTO_HASH_CLASSNAME "Mozilla Crypto Hash Function Component"
 #define NS_CRYPTO_HASH_CID {0x36a1d3b3, 0xd886, 0x4317, {0x96, 0xff, 0x87, 0xb0, 0x00, 0x5c, 0xfe, 0xf7}}
-
-#define NS_CRYPTO_HMAC_CLASSNAME "Mozilla Crypto HMAC Function Component"
 #define NS_CRYPTO_HMAC_CID {0xa496d0a2, 0xdff7, 0x4e23, {0xbd, 0x65, 0x1c, 0xa7, 0x42, 0xfa, 0x17, 0x8a}}
 
 enum EnsureNSSOperator
diff --git a/security/manager/ssl/src/nsNTLMAuthModule.h b/security/manager/ssl/src/nsNTLMAuthModule.h
index 651dc0a3717..cea8f044fb5 100644
--- a/security/manager/ssl/src/nsNTLMAuthModule.h
+++ b/security/manager/ssl/src/nsNTLMAuthModule.h
@@ -27,8 +27,6 @@ private:
   nsString mPassword;
 };
 
-#define NS_NTLMAUTHMODULE_CLASSNAME \
-  "nsNTLMAuthModule"
 #define NS_NTLMAUTHMODULE_CONTRACTID \
   NS_AUTH_MODULE_CONTRACTID_PREFIX "ntlm"
 #define NS_NTLMAUTHMODULE_CID \
diff --git a/security/manager/ssl/src/nsSDR.h b/security/manager/ssl/src/nsSDR.h
index 650f433023f..37a6480e7a2 100644
--- a/security/manager/ssl/src/nsSDR.h
+++ b/security/manager/ssl/src/nsSDR.h
@@ -27,7 +27,6 @@
 // nsSecretDecoderRing - implementation of nsISecretDecoderRing
 // ===============================================
 
-#define NS_SDR_CLASSNAME "PIPNSS Secret Decoder Ring"
 #define NS_SDR_CID \
   { 0x0c4f1ddc, 0x1dd2, 0x11b2, { 0x9d, 0x95, 0xf2, 0xfd, 0xf1, 0x13, 0x04, 0x4b } }
 
diff --git a/security/manager/ssl/src/nsSSLSocketProvider.h b/security/manager/ssl/src/nsSSLSocketProvider.h
index 87c06d11df2..63ee8140c40 100644
--- a/security/manager/ssl/src/nsSSLSocketProvider.h
+++ b/security/manager/ssl/src/nsSSLSocketProvider.h
@@ -9,7 +9,6 @@
 
 #include "nsISocketProvider.h"
 
-#define NS_SSLSOCKETPROVIDER_CLASSNAME  "Mozilla SSL Socket Provider Component"
 /* 217d014a-1dd2-11b2-999c-b0c4df79b324 */
 #define NS_SSLSOCKETPROVIDER_CID   \
 { 0x217d014a, 0x1dd2, 0x11b2, {0x99, 0x9c, 0xb0, 0xc4, 0xdf, 0x79, 0xb3, 0x24}}
diff --git a/security/manager/ssl/src/nsStreamCipher.h b/security/manager/ssl/src/nsStreamCipher.h
index 3e884c2f8ab..15dca186ce3 100644
--- a/security/manager/ssl/src/nsStreamCipher.h
+++ b/security/manager/ssl/src/nsStreamCipher.h
@@ -10,7 +10,6 @@
 #include "pk11func.h"
 #include "mozilla/Attributes.h"
 
-#define NS_STREAMCIPHER_CLASSNAME  "Stream Cipher Component"
 /* dbfcbe4a-10f7-4d6f-a481-68e6d6b71d21 */
 #define NS_STREAMCIPHER_CID   \
 { 0xdbfcbe4a, 0x10f7, 0x4d6f, {0xa4, 0x81, 0x68, 0xe6, 0xd6, 0xb7, 0x1d, 0x21}}
diff --git a/security/manager/ssl/src/nsTLSSocketProvider.h b/security/manager/ssl/src/nsTLSSocketProvider.h
index 7b8db47c0ab..69bc83728d4 100644
--- a/security/manager/ssl/src/nsTLSSocketProvider.h
+++ b/security/manager/ssl/src/nsTLSSocketProvider.h
@@ -10,7 +10,6 @@
 #include "nsISocketProvider.h"
 
 
-#define NS_STARTTLSSOCKETPROVIDER_CLASSNAME  "Mozilla STARTTLS Capable Socket Provider Component"
 #define NS_STARTTLSSOCKETPROVIDER_CID \
 { /* b9507aec-1dd1-11b2-8cd5-c48ee0c50307 */         \
      0xb9507aec,                                     \
diff --git a/toolkit/components/statusfilter/nsBrowserStatusFilter.h b/toolkit/components/statusfilter/nsBrowserStatusFilter.h
index 36b65aaab4e..2f1b428e316 100644
--- a/toolkit/components/statusfilter/nsBrowserStatusFilter.h
+++ b/toolkit/components/statusfilter/nsBrowserStatusFilter.h
@@ -65,8 +65,6 @@ private:
     bool                             mDelayedProgress;
 };
 
-#define NS_BROWSERSTATUSFILTER_CLASSNAME \
-    "nsBrowserStatusFilter"
 #define NS_BROWSERSTATUSFILTER_CONTRACTID \
     "@mozilla.org/appshell/component/browser-status-filter;1"
 #define NS_BROWSERSTATUSFILTER_CID                   \
diff --git a/toolkit/system/dbus/nsDBusModule.cpp b/toolkit/system/dbus/nsDBusModule.cpp
index d26e1a1f549..9e445717914 100644
--- a/toolkit/system/dbus/nsDBusModule.cpp
+++ b/toolkit/system/dbus/nsDBusModule.cpp
@@ -12,7 +12,6 @@
 #include "nsNetworkManagerListener.h"
 #include "nsNetCID.h"
 
-#define NS_DBUS_NETWORK_LINK_SERVICE_CLASSNAME "DBus Network Link Status"
 #define NS_DBUS_NETWORK_LINK_SERVICE_CID    \
   { 0x75a500a2,                                        \
     0x0030,                                            \
diff --git a/uriloader/exthandler/nsIExternalSharingAppService.idl b/uriloader/exthandler/nsIExternalSharingAppService.idl
index 3bdd5cc462e..f58f6981ddf 100644
--- a/uriloader/exthandler/nsIExternalSharingAppService.idl
+++ b/uriloader/exthandler/nsIExternalSharingAppService.idl
@@ -6,7 +6,6 @@
 
 %{C++
 #define NS_EXTERNALSHARINGAPPSERVICE_CONTRACTID    "@mozilla.org/uriloader/external-sharing-app-service;1"
-#define NS_IEXTERNALSHARINGAPPSERVICE_CLASSNAME "Mozilla Sharing App Service"
 %}
 
 
diff --git a/uriloader/exthandler/nsIHelperAppLauncherDialog.idl b/uriloader/exthandler/nsIHelperAppLauncherDialog.idl
index d896facae6d..7732cb5c1a8 100644
--- a/uriloader/exthandler/nsIHelperAppLauncherDialog.idl
+++ b/uriloader/exthandler/nsIHelperAppLauncherDialog.idl
@@ -84,5 +84,4 @@ interface nsIHelperAppLauncherDialog : nsISupports {
 
 %{C++
 #define NS_HELPERAPPLAUNCHERDLG_CONTRACTID    "@mozilla.org/helperapplauncherdialog;1"
-#define NS_IHELPERAPPLAUNCHERDLG_CLASSNAME "Mozilla Helper App Launcher Confirmation Dialog"
 %}
diff --git a/uriloader/prefetch/nsCPrefetchService.h b/uriloader/prefetch/nsCPrefetchService.h
index deb10f1933c..d74d89fe7bb 100644
--- a/uriloader/prefetch/nsCPrefetchService.h
+++ b/uriloader/prefetch/nsCPrefetchService.h
@@ -10,8 +10,6 @@
 /**
  * nsPrefetchService : nsIPrefetchService
  */
-#define NS_PREFETCHSERVICE_CLASSNAME \
-    "nsPrefetchService"
 #define NS_PREFETCHSERVICE_CONTRACTID \
     "@mozilla.org/prefetch-service;1"
 #define NS_PREFETCHSERVICE_CID                       \
@@ -26,8 +24,6 @@
  * nsOfflineCacheUpdateService : nsIOfflineCacheUpdateService
  */
 
-#define NS_OFFLINECACHEUPDATESERVICE_CLASSNAME \
-  "nsOfflineCacheUpdateService"
 #define NS_OFFLINECACHEUPDATESERVICE_CONTRACTID \
   "@mozilla.org/offlinecacheupdate-service;1"
 #define NS_OFFLINECACHEUPDATESERVICE_CID             \
@@ -42,8 +38,6 @@
  * nsOfflineCacheUpdate : nsIOfflineCacheUpdate
  */
 
-#define NS_OFFLINECACHEUPDATE_CLASSNAME \
-  "nsOfflineCacheUpdate"
 #define NS_OFFLINECACHEUPDATE_CONTRACTID \
   "@mozilla.org/offlinecacheupdate;1"
 #define NS_OFFLINECACHEUPDATE_CID                    \
diff --git a/widget/cocoa/nsMacWebAppUtils.h b/widget/cocoa/nsMacWebAppUtils.h
index 6e1ba6ef024..9d34df3d2c0 100644
--- a/widget/cocoa/nsMacWebAppUtils.h
+++ b/widget/cocoa/nsMacWebAppUtils.h
@@ -7,7 +7,6 @@
 #include "nsIMacWebAppUtils.h"
 
 #define NS_MACWEBAPPUTILS_CONTRACTID "@mozilla.org/widget/mac-web-app-utils;1"
-#define NS_MACWEBAPPUTILS_COMPONENT_CLASSNAME "Mac Web Application Utils"
 
 class nsMacWebAppUtils : public nsIMacWebAppUtils {
 public:
diff --git a/xpcom/base/nsDebugImpl.h b/xpcom/base/nsDebugImpl.h
index 0e277336143..8f7c7a32b9d 100644
--- a/xpcom/base/nsDebugImpl.h
+++ b/xpcom/base/nsDebugImpl.h
@@ -26,7 +26,6 @@ public:
 
 
 #define NS_DEBUG_CONTRACTID "@mozilla.org/xpcom/debug;1"
-#define NS_DEBUG_CLASSNAME  "nsDebug Interface"
 #define NS_DEBUG_CID                                 \
 { /* a80b1fb3-aaf6-4852-b678-c27eb7a518af */         \
   0xa80b1fb3,                                        \
diff --git a/xpcom/base/nsIAllocator.h b/xpcom/base/nsIAllocator.h
index ec782e0be83..b68498106f8 100644
--- a/xpcom/base/nsIAllocator.h
+++ b/xpcom/base/nsIAllocator.h
@@ -18,7 +18,6 @@
 
 #define NS_IALLOCATOR_IID       NS_GET_IID(nsIMemory)
 #define NS_ALLOCATOR_CONTRACTID NS_MEMORY_CONTRACTID
-#define NS_ALLOCATOR_CLASSNAME  NS_MEMORY_CLASSNAME
 #define NS_ALLOCATOR_CID        NS_MEMORY_CID
 
 #endif /* nsIAllocator_h___ */
diff --git a/xpcom/base/nsIConsoleService.idl b/xpcom/base/nsIConsoleService.idl
index 71d63a7883b..15e5a3c5105 100644
--- a/xpcom/base/nsIConsoleService.idl
+++ b/xpcom/base/nsIConsoleService.idl
@@ -47,8 +47,6 @@ interface nsIConsoleService : nsISupports
 
 
 %{ C++
-#define NS_CONSOLESERVICE_CLASSNAME "Console Service"
-
 #define NS_CONSOLESERVICE_CID \
 { 0x7e3ff85c, 0x1dd2, 0x11b2, { 0x8d, 0x4b, 0xeb, 0x45, 0x2c, 0xb0, 0xff, 0x40 }}
 
diff --git a/xpcom/base/nsIExceptionService.idl b/xpcom/base/nsIExceptionService.idl
index 6d4bf473a93..1a9d75d8d53 100644
--- a/xpcom/base/nsIExceptionService.idl
+++ b/xpcom/base/nsIExceptionService.idl
@@ -56,7 +56,6 @@ interface nsIExceptionService : nsIExceptionManager
 
 
 %{ C++
-#define NS_EXCEPTIONSERVICE_CLASSNAME "Exception Service"
 // {35A88F54-F267-4414-92A7-191F6454AB52}
 #define NS_EXCEPTIONSERVICE_CID \
 { 0x35a88f54, 0xf267, 0x4414, { 0x92, 0xa7, 0x19, 0x1f, 0x64, 0x54, 0xab, 0x52 } }
diff --git a/xpcom/base/nsMacUtilsImpl.h b/xpcom/base/nsMacUtilsImpl.h
index 928631775e9..2fd38fb99a4 100644
--- a/xpcom/base/nsMacUtilsImpl.h
+++ b/xpcom/base/nsMacUtilsImpl.h
@@ -30,7 +30,6 @@ private:
 
 // Global singleton service
 // 697BD3FD-43E5-41CE-AD5E-C339175C0818
-#define NS_MACUTILSIMPL_CLASSNAME "Mac OS X Utilities"
 #define NS_MACUTILSIMPL_CID \
  {0x697BD3FD, 0x43E5, 0x41CE, {0xAD, 0x5E, 0xC3, 0x39, 0x17, 0x5C, 0x08, 0x18}}
 #define NS_MACUTILSIMPL_CONTRACTID "@mozilla.org/xpcom/mac-utils;1"
diff --git a/xpcom/base/nsSystemInfo.h b/xpcom/base/nsSystemInfo.h
index d85a9b99833..d8e78340b95 100644
--- a/xpcom/base/nsSystemInfo.h
+++ b/xpcom/base/nsSystemInfo.h
@@ -25,7 +25,6 @@ private:
 };
 
 #define NS_SYSTEMINFO_CONTRACTID "@mozilla.org/system-info;1"
-#define NS_SYSTEMINFO_CLASSNAME "System Info Service"
 #define NS_SYSTEMINFO_CID \
 { 0xd962398a, 0x99e5, 0x49b2, \
 { 0x85, 0x7a, 0xc1, 0x59, 0x04, 0x9c, 0x7f, 0x6c } }
diff --git a/xpcom/base/nsTraceRefcntImpl.h b/xpcom/base/nsTraceRefcntImpl.h
index 9a4f79e1f4c..eb71ca864e1 100644
--- a/xpcom/base/nsTraceRefcntImpl.h
+++ b/xpcom/base/nsTraceRefcntImpl.h
@@ -44,7 +44,6 @@ public:
 };
 
 #define NS_TRACE_REFCNT_CONTRACTID "@mozilla.org/xpcom/trace-refcnt;1"
-#define NS_TRACE_REFCNT_CLASSNAME  "nsTraceRefcnt Interface"
 #define NS_TRACE_REFCNT_CID                          \
 { /* e3e7511e-a395-4924-94b1-d527861cded4 */         \
     0xe3e7511e,                                      \
diff --git a/xpcom/base/nsUUIDGenerator.h b/xpcom/base/nsUUIDGenerator.h
index c1a0000f5ea..b7df6e50c54 100644
--- a/xpcom/base/nsUUIDGenerator.h
+++ b/xpcom/base/nsUUIDGenerator.h
@@ -35,7 +35,6 @@ protected:
 };
 
 #define NS_UUID_GENERATOR_CONTRACTID "@mozilla.org/uuid-generator;1"
-#define NS_UUID_GENERATOR_CLASSNAME "UUID Generator"
 #define NS_UUID_GENERATOR_CID \
 { 0x706d36bb, 0xbf79, 0x4293, \
 { 0x81, 0xf2, 0x8f, 0x68, 0x28, 0xc1, 0x8f, 0x9d } }
diff --git a/xpcom/base/nsVersionComparatorImpl.h b/xpcom/base/nsVersionComparatorImpl.h
index 249d1902713..44fe8d3f35e 100644
--- a/xpcom/base/nsVersionComparatorImpl.h
+++ b/xpcom/base/nsVersionComparatorImpl.h
@@ -19,5 +19,3 @@ public:
 #define NS_VERSIONCOMPARATOR_CID \
 { 0xc6e47036, 0xca94, 0x4be3, \
   { 0x96, 0x3a, 0x9a, 0xbd, 0x87, 0x05, 0xf7, 0xa8 } }
-
-#define NS_VERSIONCOMPARATOR_CLASSNAME "nsVersionComparatorImpl"
diff --git a/xpcom/ds/nsArray.h b/xpcom/ds/nsArray.h
index 8e308bdda6e..cbf733830e5 100644
--- a/xpcom/ds/nsArray.h
+++ b/xpcom/ds/nsArray.h
@@ -12,9 +12,6 @@
 #include "nsCycleCollectionParticipant.h"
 #include "mozilla/Attributes.h"
 
-#define NS_ARRAY_CLASSNAME \
-  "nsIArray implementation"
-
 // {35C66FD1-95E9-4e0a-80C5-C3BD2B375481}
 #define NS_ARRAY_CID \
 { 0x35c66fd1, 0x95e9, 0x4e0a, \
diff --git a/xpcom/ds/nsIAtomService.idl b/xpcom/ds/nsIAtomService.idl
index ab0b53d8adc..2270445c637 100644
--- a/xpcom/ds/nsIAtomService.idl
+++ b/xpcom/ds/nsIAtomService.idl
@@ -14,7 +14,6 @@
     {0x88, 0x18, 0x98, 0xf5, 0x47, 0x5a, 0x49, 0x0c} }
 
 #define NS_ATOMSERVICE_CONTRACTID "@mozilla.org/atom-service;1"
-#define NS_ATOMSERVICE_CLASSNAME "Atom Service"
 %}
 
 /*
diff --git a/xpcom/ds/nsIByteBuffer.h b/xpcom/ds/nsIByteBuffer.h
index 8771f20d3b2..4c7c4977026 100644
--- a/xpcom/ds/nsIByteBuffer.h
+++ b/xpcom/ds/nsIByteBuffer.h
@@ -18,7 +18,6 @@ class nsIInputStream;
 { 0xe4a6e4b0, 0x93b4, 0x11d1, \
   {0x89, 0x5b, 0x00, 0x60, 0x08, 0x91, 0x1b, 0x81} }
 #define NS_BYTEBUFFER_CONTRACTID "@mozilla.org/byte-buffer;1"
-#define NS_BYTEBUFFER_CLASSNAME "Byte Buffer"
 
 /** Interface to a buffer that holds bytes */
 class nsIByteBuffer : public nsISupports {
diff --git a/xpcom/ds/nsIPersistentProperties2.idl b/xpcom/ds/nsIPersistentProperties2.idl
index dafa263f4bb..9fbb2619c4a 100644
--- a/xpcom/ds/nsIPersistentProperties2.idl
+++ b/xpcom/ds/nsIPersistentProperties2.idl
@@ -65,7 +65,6 @@ interface nsIPersistentProperties : nsIProperties
   { 0x9b, 0x8b, 0x0, 0x80, 0x5f, 0x8a, 0x16, 0xd9 } }
 
 #define NS_PERSISTENTPROPERTIES_CONTRACTID "@mozilla.org/persistent-properties;1"
-#define NS_PERSISTENTPROPERTIES_CLASSNAME "Persistent Properties"
 
 %}
 
diff --git a/xpcom/ds/nsISupportsArray.idl b/xpcom/ds/nsISupportsArray.idl
index 8b64d50b441..2cd71a28c1a 100644
--- a/xpcom/ds/nsISupportsArray.idl
+++ b/xpcom/ds/nsISupportsArray.idl
@@ -28,7 +28,6 @@ class nsISupportsArray;
     {0x93, 0x31, 0x00, 0x10, 0x4b, 0xa0, 0xfd, 0x40} \
 }
 #define NS_SUPPORTSARRAY_CONTRACTID "@mozilla.org/supports-array;1"
-#define NS_SUPPORTSARRAY_CLASSNAME "Supports Array"
  
 %}
 
diff --git a/xpcom/ds/nsObserverService.h b/xpcom/ds/nsObserverService.h
index 3730804d66e..53e27f2a8ad 100644
--- a/xpcom/ds/nsObserverService.h
+++ b/xpcom/ds/nsObserverService.h
@@ -11,8 +11,6 @@
 #include "nsTHashtable.h"
 #include "mozilla/Attributes.h"
 
-#define NS_OBSERVERSERVICE_CLASSNAME "Observer Service"
-
 // {D07F5195-E3D1-11d2-8ACD-00105A1B8860}
 #define NS_OBSERVERSERVICE_CID \
     { 0xd07f5195, 0xe3d1, 0x11d2, { 0x8a, 0xcd, 0x0, 0x10, 0x5a, 0x1b, 0x88, 0x60 } }
diff --git a/xpcom/ds/nsVariant.h b/xpcom/ds/nsVariant.h
index e62df5f1df2..181a543c35d 100644
--- a/xpcom/ds/nsVariant.h
+++ b/xpcom/ds/nsVariant.h
@@ -175,6 +175,4 @@ protected:
     0x11d5,                                  \
     {0x90, 0xef, 0x0, 0x10, 0xa4, 0xe7, 0x3d, 0x9a}}
 
-#define NS_VARIANT_CLASSNAME "Variant"
-
 #endif // nsVariant_h
diff --git a/xpcom/ds/nsWindowsRegKey.h b/xpcom/ds/nsWindowsRegKey.h
index af9c5b39b7d..def9c3b91a6 100644
--- a/xpcom/ds/nsWindowsRegKey.h
+++ b/xpcom/ds/nsWindowsRegKey.h
@@ -28,8 +28,6 @@ NS_NewWindowsRegKey(nsIWindowsRegKey **result);
 
 #ifdef _IMPL_NS_COM
 
-#define NS_WINDOWSREGKEY_CLASSNAME "nsWindowsRegKey"
-
 // a53bc624-d577-4839-b8ec-bb5040a52ff4
 #define NS_WINDOWSREGKEY_CID \
   { 0xa53bc624, 0xd577, 0x4839, \
diff --git a/xpcom/glue/nsMemory.h b/xpcom/glue/nsMemory.h
index a40744f42a4..a9920605ae5 100644
--- a/xpcom/glue/nsMemory.h
+++ b/xpcom/glue/nsMemory.h
@@ -10,7 +10,6 @@
 #include "nsIMemory.h"
 
 #define NS_MEMORY_CONTRACTID "@mozilla.org/xpcom/memory-service;1"
-#define NS_MEMORY_CLASSNAME  "Global Memory Service"
 #define NS_MEMORY_CID                                \
 { /* 30a04e40-38e7-11d4-8cf5-0060b0fc14a3 */         \
     0x30a04e40,                                      \
diff --git a/xpcom/io/nsBinaryStream.h b/xpcom/io/nsBinaryStream.h
index a521ab37f69..3748baf8f57 100644
--- a/xpcom/io/nsBinaryStream.h
+++ b/xpcom/io/nsBinaryStream.h
@@ -21,7 +21,6 @@
 }
 
 #define NS_BINARYOUTPUTSTREAM_CONTRACTID "@mozilla.org/binaryoutputstream;1"
-#define NS_BINARYOUTPUTSTREAM_CLASSNAME "Binary Output Stream"
 
 // Derive from nsIObjectOutputStream so this class can be used as a superclass
 // by nsObjectOutputStream.
@@ -61,7 +60,6 @@ protected:
 }
 
 #define NS_BINARYINPUTSTREAM_CONTRACTID "@mozilla.org/binaryinputstream;1"
-#define NS_BINARYINPUTSTREAM_CLASSNAME "Binary Input Stream"
 
 // Derive from nsIObjectInputStream so this class can be used as a superclass
 // by nsObjectInputStream.
diff --git a/xpcom/io/nsIOUtil.h b/xpcom/io/nsIOUtil.h
index 9300fe1fdd0..3e06ddb8890 100644
--- a/xpcom/io/nsIOUtil.h
+++ b/xpcom/io/nsIOUtil.h
@@ -6,7 +6,6 @@
 #ifndef nsIOUtil_h__
 #define nsIOUtil_h__
 
-#define NS_IOUTIL_CLASSNAME "XPCOM I/O utility class"
 #define NS_IOUTIL_CID                                                \
 { 0xeb833911, 0x4f49, 0x4623,                                        \
     { 0x84, 0x5f, 0xe5, 0x8a, 0x8e, 0x6d, 0xe4, 0xc2 } }
diff --git a/xpcom/io/nsMultiplexInputStream.h b/xpcom/io/nsMultiplexInputStream.h
index 298eec86112..2d472d1f7af 100644
--- a/xpcom/io/nsMultiplexInputStream.h
+++ b/xpcom/io/nsMultiplexInputStream.h
@@ -13,7 +13,6 @@
 
 #include "nsIMultiplexInputStream.h"
 
-#define NS_MULTIPLEXINPUTSTREAM_CLASSNAME  "nsMultiplexInputStream"
 #define NS_MULTIPLEXINPUTSTREAM_CONTRACTID "@mozilla.org/io/multiplex-input-stream;1"
 #define NS_MULTIPLEXINPUTSTREAM_CID                  \
 { /* 565e3a2c-1dd2-11b2-8da1-b4cef17e568d */         \
diff --git a/xpcom/io/nsPipe.h b/xpcom/io/nsPipe.h
index d9141770102..383065bd053 100644
--- a/xpcom/io/nsPipe.h
+++ b/xpcom/io/nsPipe.h
@@ -7,8 +7,6 @@
 #ifndef nsPipe_h__
 #define nsPipe_h__
 
-#define NS_PIPE_CLASSNAME \
-  "nsPipe"
 #define NS_PIPE_CONTRACTID \
   "@mozilla.org/pipe;1"
 #define NS_PIPE_CID \
diff --git a/xpcom/io/nsScriptableInputStream.h b/xpcom/io/nsScriptableInputStream.h
index b66c2716ae1..080816c7fc3 100644
--- a/xpcom/io/nsScriptableInputStream.h
+++ b/xpcom/io/nsScriptableInputStream.h
@@ -15,7 +15,6 @@
 { 0x7225c040, 0xa9bf, 0x11d3, { 0xa1, 0x97, 0x0, 0x50, 0x4, 0x1c, 0xaf, 0x44 } }
 
 #define NS_SCRIPTABLEINPUTSTREAM_CONTRACTID "@mozilla.org/scriptableinputstream;1"
-#define NS_SCRIPTABLEINPUTSTREAM_CLASSNAME "Scriptable Input Stream"
 
 class nsScriptableInputStream MOZ_FINAL : public nsIScriptableInputStream {
 public:
diff --git a/xpcom/io/nsStorageStream.h b/xpcom/io/nsStorageStream.h
index 8659ba16e12..e50ce3ffc69 100644
--- a/xpcom/io/nsStorageStream.h
+++ b/xpcom/io/nsStorageStream.h
@@ -28,7 +28,6 @@
 }
 
 #define NS_STORAGESTREAM_CONTRACTID "@mozilla.org/storagestream;1"
-#define NS_STORAGESTREAM_CLASSNAME "Storage Stream"
 
 class nsSegmentedBuffer;
 
diff --git a/xpcom/io/nsStringStream.h b/xpcom/io/nsStringStream.h
index 2f5405cfd60..5b5c66eef65 100644
--- a/xpcom/io/nsStringStream.h
+++ b/xpcom/io/nsStringStream.h
@@ -17,7 +17,6 @@
  *   nsISeekableStream
  *   nsISupportsCString
  */
-#define NS_STRINGINPUTSTREAM_CLASSNAME  "nsStringInputStream"
 #define NS_STRINGINPUTSTREAM_CONTRACTID "@mozilla.org/io/string-input-stream;1"
 #define NS_STRINGINPUTSTREAM_CID                     \
 { /* 0abb0835-5000-4790-af28-61b3ba17c295 */         \
diff --git a/xpcom/reflect/xptinfo/public/nsIInterfaceInfoManager.idl b/xpcom/reflect/xptinfo/public/nsIInterfaceInfoManager.idl
index bd476f6e2a8..1789728a265 100644
--- a/xpcom/reflect/xptinfo/public/nsIInterfaceInfoManager.idl
+++ b/xpcom/reflect/xptinfo/public/nsIInterfaceInfoManager.idl
@@ -39,9 +39,6 @@ interface nsIInterfaceInfoSuperManager : nsIInterfaceInfoManager
 };
 
 %{C++
-#define NS_INTERFACEINFOMANAGER_SERVICE_CLASSNAME  \
-   "Interface Information Manager Service"
-
 #define NS_INTERFACEINFOMANAGER_SERVICE_CID            \
  { /* 13bef784-f8e0-4f96-85c1-09f9ef4f9a19 */          \
   0x13bef784, 0xf8e0, 0x4f96,                          \
diff --git a/xpcom/threads/nsIProcess.idl b/xpcom/threads/nsIProcess.idl
index e29bf116572..49e57175ba3 100644
--- a/xpcom/threads/nsIProcess.idl
+++ b/xpcom/threads/nsIProcess.idl
@@ -96,5 +96,4 @@ interface nsIProcess : nsISupports
 %{C++
 
 #define NS_PROCESS_CONTRACTID "@mozilla.org/process/util;1"
-#define NS_PROCESS_CLASSNAME "Process Specification"
 %}
diff --git a/xpcom/threads/nsThreadManager.h b/xpcom/threads/nsThreadManager.h
index ecc867df418..a63b05e5333 100644
--- a/xpcom/threads/nsThreadManager.h
+++ b/xpcom/threads/nsThreadManager.h
@@ -66,7 +66,6 @@ private:
   bool                mInitialized;
 };
 
-#define NS_THREADMANAGER_CLASSNAME "nsThreadManager"
 #define NS_THREADMANAGER_CID                       \
 { /* 7a4204c6-e45a-4c37-8ebb-6709a22c917c */       \
   0x7a4204c6,                                      \
diff --git a/xpcom/threads/nsThreadPool.h b/xpcom/threads/nsThreadPool.h
index dce37010bab..729b4769785 100644
--- a/xpcom/threads/nsThreadPool.h
+++ b/xpcom/threads/nsThreadPool.h
@@ -45,7 +45,6 @@ private:
   nsThreadPoolNaming    mThreadNaming;
 };
 
-#define NS_THREADPOOL_CLASSNAME "nsThreadPool"
 #define NS_THREADPOOL_CID                          \
 { /* 547ec2a8-315e-4ec4-888e-6e4264fe90eb */       \
   0x547ec2a8,                                      \
diff --git a/xpcom/threads/nsTimerImpl.h b/xpcom/threads/nsTimerImpl.h
index 2c8036dd6d4..c318cf10620 100644
--- a/xpcom/threads/nsTimerImpl.h
+++ b/xpcom/threads/nsTimerImpl.h
@@ -25,7 +25,6 @@ extern PRLogModuleInfo *GetTimerLog();
 #undef DEBUG_TIMERS
 #endif
 
-#define NS_TIMER_CLASSNAME "Timer"
 #define NS_TIMER_CID \
 { /* 5ff24248-1dd2-11b2-8427-fbab44f29bc8 */         \
      0x5ff24248,                                     \