diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 099ab79f636..a21a644cb2b 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -148,7 +148,6 @@
 #include "nsIJSContextStack.h"
 #include "nsIJSRuntimeService.h"
 #include "nsIMarkupDocumentViewer.h"
-#include "nsIPrefBranch.h"
 #include "nsIPresShell.h"
 #include "nsIPrivateDOMEvent.h"
 #include "nsIProgrammingLanguage.h"
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index 5ea02266466..ba5d5ad0be5 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -49,8 +49,6 @@
 #include "nsIFilePicker.h"
 #include "nsIWindowWatcher.h"
 #include "nsIDOMWindow.h"
-#include "nsIPrefBranch.h"
-#include "nsIPrefLocalizedString.h"
 #include "nsIObserverService.h"
 #include "nsContentUtils.h"
 #include "nsAutoPtr.h"
@@ -216,10 +214,7 @@ ContentParent::Init()
         obs->AddObserver(this, "a11y-init-or-shutdown", false);
 #endif
     }
-    nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
-    if (prefs) {
-        prefs->AddObserver("", this, false);
-    }
+    Preferences::AddStrongObserver(this, "");
     nsCOMPtr<nsIThreadInternal>
             threadInt(do_QueryInterface(NS_GetCurrentThread()));
     if (threadInt) {
@@ -249,13 +244,8 @@ ContentParent::OnChannelConnected(int32 pid)
         SetOtherProcess(handle);
 
 #if defined(ANDROID) || defined(LINUX)
-        EnsurePrefService();
-        nsCOMPtr<nsIPrefBranch> branch;
-        branch = do_QueryInterface(mPrefService);
-
         // Check nice preference
-        PRInt32 nice = 0;
-        branch->GetIntPref("dom.ipc.content.nice", &nice);
+        PRInt32 nice = Preferences::GetInt("dom.ipc.content.nice", 0);
 
         // Environment variable overrides preference
         char* relativeNicenessStr = getenv("MOZ_CHILD_PROCESS_RELATIVE_NICENESS");
@@ -329,11 +319,7 @@ ContentParent::ActorDestroy(ActorDestroyReason why)
     SetChildMemoryReporters(empty);
 
     // remove the global remote preferences observers
-    nsCOMPtr<nsIPrefBranch> prefs 
-            (do_GetService(NS_PREFSERVICE_CONTRACTID));
-    if (prefs) { 
-        prefs->RemoveObserver("", this);
-    }
+    Preferences::RemoveObserver(this, "");
 
     RecvRemoveGeolocationListener();
 
@@ -464,7 +450,6 @@ ContentParent::IsAlive()
 bool
 ContentParent::RecvReadPrefsArray(InfallibleTArray<PrefTuple> *prefs)
 {
-    EnsurePrefService();
     Preferences::MirrorPreferences(prefs);
     return true;
 }
@@ -478,18 +463,6 @@ ContentParent::RecvReadFontList(InfallibleTArray<FontListEntry>* retValue)
     return true;
 }
 
-
-void
-ContentParent::EnsurePrefService()
-{
-    nsresult rv;
-    if (!mPrefService) {
-        mPrefService = do_GetService(NS_PREFSERVICE_CONTRACTID, &rv);
-        NS_ASSERTION(NS_SUCCEEDED(rv), 
-                     "We lost prefService in the Chrome process !");
-    }
-}
-
 bool
 ContentParent::RecvReadPermissions(InfallibleTArray<IPC::Permission>* aPermissions)
 {
diff --git a/dom/ipc/ContentParent.h b/dom/ipc/ContentParent.h
index c768a5769f8..5c044fc2254 100644
--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -48,7 +48,6 @@
 #include "nsIObserver.h"
 #include "nsIThreadInternal.h"
 #include "nsNetUtil.h"
-#include "nsIPrefService.h"
 #include "nsIPermissionManager.h"
 #include "nsIDOMGeoPositionCallback.h"
 #include "nsIMemoryReporter.h"
@@ -167,8 +166,6 @@ private:
     virtual bool RecvReadPrefsArray(InfallibleTArray<PrefTuple> *retValue);
     virtual bool RecvReadFontList(InfallibleTArray<FontListEntry>* retValue);
 
-    void EnsurePrefService();
-
     virtual bool RecvReadPermissions(InfallibleTArray<IPC::Permission>* aPermissions);
 
     virtual bool RecvGetIndexedDBDirectory(nsString* aDirectory);
@@ -238,8 +235,6 @@ private:
     nsCOMArray<nsIMemoryReporter> mMemoryReporters;
 
     bool mIsAlive;
-    nsCOMPtr<nsIPrefService> mPrefService;
-
     bool mSendPermissionUpdates;
 
     nsRefPtr<nsFrameMessageManager> mMessageManager;
diff --git a/dom/plugins/base/nsNPAPIPlugin.cpp b/dom/plugins/base/nsNPAPIPlugin.cpp
index cbbde291f9a..1e195512145 100644
--- a/dom/plugins/base/nsNPAPIPlugin.cpp
+++ b/dom/plugins/base/nsNPAPIPlugin.cpp
@@ -55,12 +55,11 @@
 #include "nsIServiceManager.h"
 #include "nsThreadUtils.h"
 #include "nsIPrivateBrowsingService.h"
+#include "mozilla/Preferences.h"
 
 #include "nsIPluginStreamListener.h"
 #include "nsPluginsDir.h"
 #include "nsPluginSafety.h"
-#include "nsIPrefService.h"
-#include "nsIPrefBranch.h"
 #include "nsPluginLogging.h"
 
 #include "nsIJSContextStack.h"
@@ -352,7 +351,7 @@ nsNPAPIPlugin::RunPluginOOP(const nsPluginTag *aPluginTag)
   }
 #endif
 
-  nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
+  nsIPrefBranch* prefs = Preferences::GetRootBranch();
   if (!prefs) {
     return false;
   }
@@ -385,8 +384,7 @@ nsNPAPIPlugin::RunPluginOOP(const nsPluginTag *aPluginTag)
   // so use the mime type (mIsJavaPlugin) and a special pref.
   bool javaIsEnabled;
   if (aPluginTag->mIsJavaPlugin &&
-      NS_SUCCEEDED(prefs->GetBoolPref("dom.ipc.plugins.java.enabled", &javaIsEnabled)) &&
-      !javaIsEnabled) {
+      !Preferences::GetBool("dom.ipc.plugins.java.enabled", true)) {
     return false;
   }
 
@@ -417,8 +415,8 @@ nsNPAPIPlugin::RunPluginOOP(const nsPluginTag *aPluginTag)
         match = (NS_WildCardMatch(prefFile.get(), maskStart, 0) == MATCH);
       }
 
-      if (match && NS_SUCCEEDED(prefs->GetBoolPref(prefNames[currentPref],
-                                                   &oopPluginsEnabled))) {
+      if (match && NS_SUCCEEDED(Preferences::GetBool(prefNames[currentPref],
+                                                     &oopPluginsEnabled))) {
         prefSet = true;
         break;
       }
@@ -427,17 +425,17 @@ nsNPAPIPlugin::RunPluginOOP(const nsPluginTag *aPluginTag)
   }
 
   if (!prefSet) {
-    oopPluginsEnabled = false;
+    oopPluginsEnabled =
 #ifdef XP_MACOSX
 #if defined(__i386__)
-    prefs->GetBoolPref("dom.ipc.plugins.enabled.i386", &oopPluginsEnabled);
+    Preferences::GetBool("dom.ipc.plugins.enabled.i386", false);
 #elif defined(__x86_64__)
-    prefs->GetBoolPref("dom.ipc.plugins.enabled.x86_64", &oopPluginsEnabled);
+    Preferences::GetBool("dom.ipc.plugins.enabled.x86_64", false);
 #elif defined(__ppc__)
-    prefs->GetBoolPref("dom.ipc.plugins.enabled.ppc", &oopPluginsEnabled);
+    Preferences::GetBool("dom.ipc.plugins.enabled.ppc", false);
 #endif
 #else
-    prefs->GetBoolPref("dom.ipc.plugins.enabled", &oopPluginsEnabled);
+    Preferences::GetBool("dom.ipc.plugins.enabled", false);
 #endif
   }
 
@@ -2061,12 +2059,10 @@ _getvalue(NPP npp, NPNVariable variable, void *result)
 
   case NPNVjavascriptEnabledBool: {
     *(NPBool*)result = false;
-    nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
-    if (prefs) {
-      bool js = false;;
-      res = prefs->GetBoolPref("javascript.enabled", &js);
-      if (NS_SUCCEEDED(res))
-        *(NPBool*)result = js;
+    bool js = false;
+    res = Preferences::GetBool("javascript.enabled", &js);
+    if (NS_SUCCEEDED(res)) {
+      *(NPBool*)result = js;
     }
     return NPERR_NO_ERROR;
   }
diff --git a/dom/plugins/base/nsNPAPIPluginInstance.cpp b/dom/plugins/base/nsNPAPIPluginInstance.cpp
index 21ae9368fc2..4d5f091284b 100644
--- a/dom/plugins/base/nsNPAPIPluginInstance.cpp
+++ b/dom/plugins/base/nsNPAPIPluginInstance.cpp
@@ -61,6 +61,8 @@
 #include "nsNetCID.h"
 #include "nsIContent.h"
 
+#include "mozilla/Preferences.h"
+
 #ifdef MOZ_WIDGET_ANDROID
 #include "ANPBase.h"
 #include <android/log.h>
@@ -105,13 +107,8 @@ nsNPAPIPluginInstance::nsNPAPIPluginInstance()
   mNPP.pdata = NULL;
   mNPP.ndata = this;
 
-  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
-  if (prefs) {
-    bool useLayersPref;
-    nsresult rv = prefs->GetBoolPref("plugins.use_layers", &useLayersPref);
-    if (NS_SUCCEEDED(rv))
-      mUsePluginLayersPref = useLayersPref;
-  }
+  mUsePluginLayersPref =
+    Preferences::GetBool("plugins.use_layers", mUsePluginLayersPref);
 
   PLUGIN_LOG(PLUGIN_LOG_BASIC, ("nsNPAPIPluginInstance ctor: this=%p\n",this));
 }
diff --git a/dom/plugins/base/nsPluginDirServiceProvider.cpp b/dom/plugins/base/nsPluginDirServiceProvider.cpp
index ff3e68a07f8..7d2545ef78b 100644
--- a/dom/plugins/base/nsPluginDirServiceProvider.cpp
+++ b/dom/plugins/base/nsPluginDirServiceProvider.cpp
@@ -41,16 +41,16 @@
 
 #include "nsCRT.h"
 #include "nsILocalFile.h"
-#include "nsIPrefBranch.h"
-#include "nsIPrefService.h"
 #include "nsDependentString.h"
-#include "nsXPIDLString.h"
 #include "prmem.h"
 #include "nsArrayEnumerator.h"
+#include "mozilla/Preferences.h"
 
 #include <windows.h>
 #include "nsIWindowsRegKey.h"
 
+using namespace mozilla;
+
 typedef struct structVer
 {
   WORD wMajor;
@@ -231,18 +231,15 @@ nsPluginDirServiceProvider::GetFile(const char *charProp, bool *persistant,
   *_retval = nsnull;
   *persistant = false;
 
-  nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
-  if (!prefs)
-    return NS_ERROR_FAILURE;
-
   nsCOMPtr<nsIWindowsRegKey> regKey =
     do_CreateInstance("@mozilla.org/windows-registry-key;1");
   NS_ENSURE_TRUE(regKey, NS_ERROR_FAILURE);
 
   if (nsCRT::strcmp(charProp, NS_WIN_JRE_SCAN_KEY) == 0) {
-    nsXPIDLCString strVer;
-    if (NS_FAILED(prefs->GetCharPref(charProp, getter_Copies(strVer))))
+    nsAdoptingCString strVer = Preferences::GetCString(charProp);
+    if (!strVer) {
       return NS_ERROR_FAILURE;
+    }
     verBlock minVer;
     TranslateVersionStr(NS_ConvertASCIItoUTF16(strVer).get(), &minVer);
 
@@ -332,9 +329,10 @@ nsPluginDirServiceProvider::GetFile(const char *charProp, bool *persistant,
       }
     }
   } else if (nsCRT::strcmp(charProp, NS_WIN_QUICKTIME_SCAN_KEY) == 0) {
-    nsXPIDLCString strVer;
-    if (NS_FAILED(prefs->GetCharPref(charProp, getter_Copies(strVer))))
+    nsAdoptingCString strVer = Preferences::GetCString(charProp);
+    if (!strVer) {
       return NS_ERROR_FAILURE;
+    }
     verBlock minVer;
     TranslateVersionStr(NS_ConvertASCIItoUTF16(strVer).get(), &minVer);
 
@@ -371,9 +369,10 @@ nsPluginDirServiceProvider::GetFile(const char *charProp, bool *persistant,
       }
     }
   } else if (nsCRT::strcmp(charProp, NS_WIN_WMP_SCAN_KEY) == 0) {
-    nsXPIDLCString strVer;
-    if (NS_FAILED(prefs->GetCharPref(charProp, getter_Copies(strVer))))
+    nsAdoptingCString strVer = Preferences::GetCString(charProp);
+    if (!strVer) {
       return NS_ERROR_FAILURE;
+    }
     verBlock minVer;
     TranslateVersionStr(NS_ConvertASCIItoUTF16(strVer).get(), &minVer);
 
@@ -409,8 +408,8 @@ nsPluginDirServiceProvider::GetFile(const char *charProp, bool *persistant,
       }
     }
   } else if (nsCRT::strcmp(charProp, NS_WIN_ACROBAT_SCAN_KEY) == 0) {
-    nsXPIDLCString strVer;
-    if (NS_FAILED(prefs->GetCharPref(charProp, getter_Copies(strVer)))) {
+    nsAdoptingCString strVer = Preferences::GetCString(charProp);
+    if (!strVer) {
       return NS_ERROR_FAILURE;
     }
 
diff --git a/dom/plugins/base/nsPluginHost.cpp b/dom/plugins/base/nsPluginHost.cpp
index d37ef12c9dc..2edead6b53c 100644
--- a/dom/plugins/base/nsPluginHost.cpp
+++ b/dom/plugins/base/nsPluginHost.cpp
@@ -80,7 +80,6 @@
 #include "nsHashtable.h"
 #include "nsIProxyInfo.h"
 #include "nsPluginLogging.h"
-#include "nsIPrefBranch.h"
 #include "nsIScriptChannel.h"
 #include "nsIBlocklistService.h"
 #include "nsVersionComparator.h"
@@ -88,6 +87,7 @@
 #include "nsIObjectLoadingContent.h"
 #include "nsIWritablePropertyBag2.h"
 #include "nsPluginStreamListenerPeer.h"
+#include "mozilla/Preferences.h"
 
 #include "nsEnumeratorUtils.h"
 #include "nsXPCOM.h"
@@ -336,17 +336,7 @@ NS_IMETHODIMP nsPluginDocReframeEvent::Run() {
 
 static bool UnloadPluginsASAP()
 {
-  nsresult rv;
-  nsCOMPtr<nsIPrefBranch> pref(do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
-  if (NS_SUCCEEDED(rv)) {
-    bool unloadPluginsASAP = false;
-    rv = pref->GetBoolPref("dom.ipc.plugins.unloadASAP", &unloadPluginsASAP);
-    if (NS_SUCCEEDED(rv)) {
-      return unloadPluginsASAP;
-    }
-  }
-
-  return false;
+  return Preferences::GetBool("dom.ipc.plugins.unloadASAP", false);
 }
 
 nsPluginHost::nsPluginHost()
@@ -355,20 +345,10 @@ nsPluginHost::nsPluginHost()
 {
   // check to see if pref is set at startup to let plugins take over in
   // full page mode for certain image mime types that we handle internally
-  mPrefService = do_GetService(NS_PREFSERVICE_CONTRACTID);
-  if (mPrefService) {
-    bool tmp;
-    nsresult rv = mPrefService->GetBoolPref("plugin.override_internal_types",
-                                            &tmp);
-    if (NS_SUCCEEDED(rv)) {
-      mOverrideInternalTypes = tmp;
-    }
+  mOverrideInternalTypes =
+    Preferences::GetBool("plugin.override_internal_types", false);
 
-    rv = mPrefService->GetBoolPref("plugin.disable", &tmp);
-    if (NS_SUCCEEDED(rv)) {
-      mPluginsDisabled = tmp;
-    }
-  }
+  mPluginsDisabled = Preferences::GetBool("plugin.disable", false);
 
   nsCOMPtr<nsIObserverService> obsService =
     mozilla::services::GetObserverService();
@@ -866,8 +846,6 @@ nsresult nsPluginHost::Destroy()
   }
 #endif /* XP_WIN */
 
-  mPrefService = nsnull; // release prefs service to avoid leaks!
-
   return NS_OK;
 }
 
@@ -1454,11 +1432,7 @@ public:
 
   NS_METHOD GetFilename(nsAString& aFilename)
   {
-    bool bShowPath;
-    nsCOMPtr<nsIPrefBranch> prefService = do_GetService(NS_PREFSERVICE_CONTRACTID);
-    if (prefService &&
-        NS_SUCCEEDED(prefService->GetBoolPref("plugin.expose_full_path", &bShowPath)) &&
-        bShowPath) {
+    if (Preferences::GetBool("plugin.expose_full_path", false)) {
       CopyUTF8toUTF16(mPluginTag.mFullPath, aFilename);
     } else {
       CopyUTF8toUTF16(mPluginTag.mFileName, aFilename);
@@ -2219,7 +2193,7 @@ nsresult nsPluginHost::ScanPluginsDirectory(nsIFile *pluginsDir,
   }
 
   if (warnOutdated) {
-    mPrefService->SetBoolPref("plugins.update.notifyUser", true);
+    Preferences::SetBool("plugins.update.notifyUser", true);
   }
 
   return NS_OK;
@@ -2348,10 +2322,7 @@ nsresult nsPluginHost::FindPlugins(bool aCreatePluginList, bool * aPluginsChange
                             // the rest is optional
 
 #ifdef XP_WIN
-  bool bScanPLIDs = false;
-
-  if (mPrefService)
-    mPrefService->GetBoolPref("plugin.scan.plid.all", &bScanPLIDs);
+  bool bScanPLIDs = Preferences::GetBool("plugin.scan.plid.all", false);
 
     // Now lets scan any PLID directories
   if (bScanPLIDs && mPrivateDirServiceProvider) {
@@ -3233,13 +3204,9 @@ nsPluginHost::StopPluginInstance(nsNPAPIPluginInstance* aInstance)
   bool doCache = aInstance->ShouldCache();
   if (doCache) {
     // try to get the max cached instances from a pref or use default
-    PRUint32 cachedInstanceLimit;
-    nsresult rv = NS_ERROR_FAILURE;
-    if (mPrefService)
-      rv = mPrefService->GetIntPref(NS_PREF_MAX_NUM_CACHED_INSTANCES, (int*)&cachedInstanceLimit);
-    if (NS_FAILED(rv))
-      cachedInstanceLimit = DEFAULT_NUMBER_OF_STOPPED_INSTANCES;
-    
+    PRUint32 cachedInstanceLimit =
+      Preferences::GetUint(NS_PREF_MAX_NUM_CACHED_INSTANCES,
+                           DEFAULT_NUMBER_OF_STOPPED_INSTANCES);
     if (StoppedInstanceCount() >= cachedInstanceLimit) {
       nsNPAPIPluginInstance *oldestInstance = FindOldestStoppedInstance();
       if (oldestInstance) {
diff --git a/dom/plugins/base/nsPluginHost.h b/dom/plugins/base/nsPluginHost.h
index 4ca265a514a..a840706fe91 100644
--- a/dom/plugins/base/nsPluginHost.h
+++ b/dom/plugins/base/nsPluginHost.h
@@ -53,7 +53,6 @@
 #include "nsWeakPtr.h"
 #include "nsIPrompt.h"
 #include "nsISupportsArray.h"
-#include "nsIPrefBranch.h"
 #include "nsWeakReference.h"
 #include "nsThreadUtils.h"
 #include "nsTArray.h"
@@ -322,7 +321,6 @@ private:
   nsTArray< nsRefPtr<nsNPAPIPluginInstance> > mInstances;
 
   nsCOMPtr<nsIFile> mPluginRegFile;
-  nsCOMPtr<nsIPrefBranch> mPrefService;
 #ifdef XP_WIN
   nsRefPtr<nsPluginDirServiceProvider> mPrivateDirServiceProvider;
 #endif
diff --git a/dom/plugins/base/nsPluginSafety.h b/dom/plugins/base/nsPluginSafety.h
index 801c8464eaa..98e8f4ccde7 100644
--- a/dom/plugins/base/nsPluginSafety.h
+++ b/dom/plugins/base/nsPluginSafety.h
@@ -40,8 +40,6 @@
 
 #include "npapi.h"
 #include "nsPluginHost.h"
-#include "nsIPrefBranch.h"
-#include "nsIPrefService.h"
 #include <prinrval.h>
 
 #if defined(XP_WIN)
@@ -52,14 +50,15 @@ void NS_NotifyPluginCall(PRIntervalTime);
 
 #ifdef CALL_SAFETY_ON
 
+#include "mozilla/Preferences.h"
+
 extern bool gSkipPluginSafeCalls;
 
-#define NS_INIT_PLUGIN_SAFE_CALLS                               \
-PR_BEGIN_MACRO                                                  \
-  nsresult res;                                                 \
-  nsCOMPtr<nsIPrefBranch> pref(do_GetService(NS_PREFSERVICE_CONTRACTID, &res)); \
-  if(NS_SUCCEEDED(res) && pref)                                 \
-    res = pref->GetBoolPref("plugin.dont_try_safe_calls", &gSkipPluginSafeCalls);\
+#define NS_INIT_PLUGIN_SAFE_CALLS                                  \
+PR_BEGIN_MACRO                                                     \
+  gSkipPluginSafeCalls =                                           \
+    ::mozilla::Preferences::GetBool("plugin.dont_try_safe_calls",  \
+                                    gSkipPluginSafeCalls);         \
 PR_END_MACRO
 
 #define NS_TRY_SAFE_CALL_RETURN(ret, fun, pluginInst) \
diff --git a/dom/plugins/base/nsPluginTags.cpp b/dom/plugins/base/nsPluginTags.cpp
index f6bc5b4a707..f8d8050be09 100644
--- a/dom/plugins/base/nsPluginTags.cpp
+++ b/dom/plugins/base/nsPluginTags.cpp
@@ -45,8 +45,6 @@
 #include "nsIPluginInstanceOwner.h"
 #include "nsIDocument.h"
 #include "nsServiceManagerUtils.h"
-#include "nsIPrefService.h"
-#include "nsIPrefBranch.h"
 #include "nsPluginsDir.h"
 #include "nsPluginHost.h"
 #include "nsIUnicodeDecoder.h"
@@ -56,7 +54,9 @@
 #include "nsICategoryManager.h"
 #include "nsNPAPIPlugin.h"
 #include "mozilla/TimeStamp.h"
+#include "mozilla/Preferences.h"
 
+using namespace mozilla;
 using mozilla::TimeStamp;
 
 inline char* new_str(const char* str)
@@ -388,10 +388,6 @@ nsPluginTag::RegisterWithCategoryManager(bool aOverrideInternalTypes,
   
   const char *contractId = "@mozilla.org/content/plugin/document-loader-factory;1";
   
-  nsCOMPtr<nsIPrefBranch> psvc(do_GetService(NS_PREFSERVICE_CONTRACTID));
-  if (!psvc)
-    return; // NS_ERROR_OUT_OF_MEMORY
-  
   // A preference controls whether or not the full page plugin is disabled for
   // a particular type. The string must be in the form:
   //   type1,type2,type3,type4
@@ -399,11 +395,11 @@ nsPluginTag::RegisterWithCategoryManager(bool aOverrideInternalTypes,
   // (and other plugin host settings) so applications can reliably disable 
   // plugins - without relying on implementation details such as prefs/category
   // manager entries.
-  nsXPIDLCString overrideTypes;
   nsCAutoString overrideTypesFormatted;
   if (aType != ePluginUnregister) {
-    psvc->GetCharPref("plugin.disable_full_page_plugin_for_types", getter_Copies(overrideTypes));
     overrideTypesFormatted.Assign(',');
+    nsAdoptingCString overrideTypes =
+      Preferences::GetCString("plugin.disable_full_page_plugin_for_types");
     overrideTypesFormatted += overrideTypes;
     overrideTypesFormatted.Append(',');
   }
diff --git a/dom/plugins/ipc/PluginModuleParent.cpp b/dom/plugins/ipc/PluginModuleParent.cpp
index 1fa1adb2a7c..293249254ed 100644
--- a/dom/plugins/ipc/PluginModuleParent.cpp
+++ b/dom/plugins/ipc/PluginModuleParent.cpp
@@ -41,8 +41,6 @@
 #elif XP_MACOSX
 #include "PluginInterposeOSX.h"
 #include "PluginUtilsOSX.h"
-#include "nsIPrefService.h"
-#include "nsIPrefBranch.h"
 #endif
 #ifdef MOZ_WIDGET_QT
 #include <QtCore/QCoreApplication>
@@ -1163,15 +1161,8 @@ PluginModuleParent::RecvGetNativeCursorsSupported(bool* supported)
 {
     PLUGIN_LOG_DEBUG(("%s", FULLFUNCTION));
 #if defined(XP_MACOSX)
-    bool nativeCursorsSupported = false;
-    nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
-    if (prefs) {
-      if (NS_FAILED(prefs->GetBoolPref("dom.ipc.plugins.nativeCursorSupport",
-          &nativeCursorsSupported))) {
-        nativeCursorsSupported = false;
-      }
-    }
-    *supported = nativeCursorsSupported;
+    *supported =
+      Preferences::GetBool("dom.ipc.plugins.nativeCursorSupport", false);
     return true;
 #else
     NS_NOTREACHED(
diff --git a/dom/src/geolocation/nsGeolocation.cpp b/dom/src/geolocation/nsGeolocation.cpp
index 3bb87b40e68..26078edab4e 100644
--- a/dom/src/geolocation/nsGeolocation.cpp
+++ b/dom/src/geolocation/nsGeolocation.cpp
@@ -66,8 +66,6 @@
 #include "nsIURI.h"
 #include "nsIPermissionManager.h"
 #include "nsIObserverService.h"
-#include "nsIPrefService.h"
-#include "nsIPrefBranch.h"
 #include "nsIJSContextStack.h"
 #include "nsThreadUtils.h"
 #include "mozilla/Services.h"
diff --git a/dom/src/storage/nsDOMStorage.cpp b/dom/src/storage/nsDOMStorage.cpp
index 116752d6ca1..d3e7ff85e8d 100644
--- a/dom/src/storage/nsDOMStorage.cpp
+++ b/dom/src/storage/nsDOMStorage.cpp
@@ -61,7 +61,6 @@ using mozilla::dom::StorageChild;
 #include "nsReadableUtils.h"
 #include "nsIObserverService.h"
 #include "nsNetUtil.h"
-#include "nsIPrefBranch.h"
 #include "nsICookiePermission.h"
 #include "nsIPermission.h"
 #include "nsIPermissionManager.h"
diff --git a/dom/system/nsDeviceSensors.cpp b/dom/system/nsDeviceSensors.cpp
index d350929dc04..227a35601df 100644
--- a/dom/system/nsDeviceSensors.cpp
+++ b/dom/system/nsDeviceSensors.cpp
@@ -48,7 +48,8 @@
 #include "nsIServiceManager.h"
 #include "nsIPrivateDOMEvent.h"
 #include "nsIServiceManager.h"
-#include "nsIPrefService.h"
+
+#include "mozilla/Preferences.h"
 
 using namespace mozilla;
 using namespace hal;
@@ -122,17 +123,9 @@ NS_IMETHODIMP nsDeviceSensorData::GetZ(double *aZ)
 NS_IMPL_ISUPPORTS1(nsDeviceSensors, nsIDeviceSensors)
 
 nsDeviceSensors::nsDeviceSensors()
-: mEnabled(true)
 {
   mLastDOMMotionEventTime = TimeStamp::Now();
-
-  nsCOMPtr<nsIPrefBranch> prefSrv = do_GetService(NS_PREFSERVICE_CONTRACTID);
-  if (prefSrv) {
-    bool bvalue;
-    nsresult rv = prefSrv->GetBoolPref("device.motion.enabled", &bvalue);
-    if (NS_SUCCEEDED(rv) && bvalue == false)
-      mEnabled = false;
-  }
+  mEnabled = Preferences::GetBool("device.motion.enabled", true);
 
   for (int i = 0; i < NUM_SENSOR_TYPE; i++) {
     nsTArray<nsIDOMWindow*> *windows = new nsTArray<nsIDOMWindow*>();
diff --git a/dom/system/unix/MaemoLocationProvider.cpp b/dom/system/unix/MaemoLocationProvider.cpp
index 440e3c3a239..1412109fe0c 100644
--- a/dom/system/unix/MaemoLocationProvider.cpp
+++ b/dom/system/unix/MaemoLocationProvider.cpp
@@ -41,10 +41,11 @@
 #include "MaemoLocationProvider.h"
 #include "nsIClassInfo.h"
 #include "nsDOMClassInfoID.h"
-#include "nsIPrefService.h"
-#include "nsIPrefBranch.h"
 #include "nsIServiceManager.h"
 #include "nsServiceManagerUtils.h"
+#include "mozilla/Preferences.h"
+
+using namespace mozilla;
 
 NS_IMPL_ISUPPORTS2(MaemoLocationProvider, nsIGeolocationProvider, nsITimerCallback)
 
@@ -192,31 +193,31 @@ NS_IMETHODIMP MaemoLocationProvider::Startup()
 {
   nsresult rv(NS_OK);
 
-  nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
-  if (!prefs)
-    return NS_ERROR_FAILURE;
-
   rv = StartControl();
   NS_ENSURE_SUCCESS(rv, rv);
 
   rv = StartDevice();
   NS_ENSURE_SUCCESS(rv, rv);
 
-  prefs->GetBoolPref("geo.herror.ignore.big", &mIgnoreBigHErr);
+  mIgnoreBigHErr =
+    Preferences::GetBool("geo.herror.ignore.big", mIgnoreBigHErr);
 
-  if (mIgnoreBigHErr)
-    prefs->GetIntPref("geo.herror.max.value", &mMaxHErr);
+  if (mIgnoreBigHErr) {
+    mMaxHErr = Preferences::GetInt("geo.herror.max.value", mMaxHErr);
+  }
 
-  prefs->GetBoolPref("geo.verror.ignore.big", &mIgnoreBigVErr);
+  mIgnoreBigVErr =
+    Preferences::GetBool("geo.verror.ignore.big", mIgnoreBigVErr);
 
-  if (mIgnoreBigVErr)
-    prefs->GetIntPref("geo.verror.max.value", &mMaxVErr);
+  if (mIgnoreBigVErr) {
+    mMaxVErr = Preferences::GetInt("geo.verror.max.value", mMaxVErr);
+  }
 
   if (mUpdateTimer)
     return NS_OK;
 
-  PRInt32 update = 0; //0 second no timer created
-  prefs->GetIntPref("geo.default.update", &update);
+  // 0 second no timer created
+  PRInt32 update = Preferences::GetInt("geo.default.update", 0);
 
   if (!update)
     return NS_OK;