diff --git a/docshell/base/LoadContext.cpp b/docshell/base/LoadContext.cpp
index 605ada9734b..be7da52610f 100644
--- a/docshell/base/LoadContext.cpp
+++ b/docshell/base/LoadContext.cpp
@@ -34,7 +34,7 @@ nsILoadContext::GetOriginAttributes(mozilla::DocShellOriginAttributes& aAttrs)
   aAttrs = attrs;
   return true;
 }
-  
+
 namespace mozilla {
 
 NS_IMPL_ISUPPORTS(LoadContext, nsILoadContext, nsIInterfaceRequestor)
@@ -172,13 +172,13 @@ LoadContext::SetRemoteTabs(bool aUseRemoteTabs)
 }
 
 NS_IMETHODIMP
-LoadContext::GetIsInBrowserElement(bool* aIsInBrowserElement)
+LoadContext::GetIsInIsolatedMozBrowserElement(bool* aIsInIsolatedMozBrowserElement)
 {
   MOZ_ASSERT(mIsNotNull);
 
-  NS_ENSURE_ARG_POINTER(aIsInBrowserElement);
+  NS_ENSURE_ARG_POINTER(aIsInIsolatedMozBrowserElement);
 
-  *aIsInBrowserElement = mOriginAttributes.mInIsolatedMozBrowser;
+  *aIsInIsolatedMozBrowserElement = mOriginAttributes.mInIsolatedMozBrowser;
   return NS_OK;
 }
 
diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 9cd3c684aa8..33674234588 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -3500,7 +3500,8 @@ nsDocShell::CanAccessItem(nsIDocShellTreeItem* aTargetItem,
     return false;
   }
 
-  if (targetDS->GetIsInBrowserElement() != accessingDS->GetIsInBrowserElement() ||
+  if (targetDS->GetIsInIsolatedMozBrowserElement() !=
+        accessingDS->GetIsInIsolatedMozBrowserElement() ||
       targetDS->GetAppId() != accessingDS->GetAppId()) {
     return false;
   }
@@ -13938,9 +13939,9 @@ nsDocShell::GetInheritedFrameType()
 }
 
 /* [infallible] */ NS_IMETHODIMP
-nsDocShell::GetIsInBrowserElement(bool* aIsInBrowserElement)
+nsDocShell::GetIsInIsolatedMozBrowserElement(bool* aIsInIsolatedMozBrowserElement)
 {
-  *aIsInBrowserElement = (GetInheritedFrameType() == eFrameTypeBrowser);
+  *aIsInIsolatedMozBrowserElement = (GetInheritedFrameType() == eFrameTypeBrowser);
   return NS_OK;
 }
 
diff --git a/docshell/base/nsIDocShell.idl b/docshell/base/nsIDocShell.idl
index 7654e64b75d..ba07aa46c83 100644
--- a/docshell/base/nsIDocShell.idl
+++ b/docshell/base/nsIDocShell.idl
@@ -780,16 +780,21 @@ interface nsIDocShell : nsIDocShellTreeItem
   [infallible] readonly attribute boolean isBrowserOrApp;
 
   /**
-   * Returns true if this docshell corresponds to an <iframe mozbrowser> or if
-   * the docshell is contained in an <iframe mozbrowser>.  (<iframe mozapp
-   * mozbrowser> does not count as a browser.)
+   * Returns true if this docshell corresponds to an isolated <iframe
+   * mozbrowser> or if the docshell is contained in an isolated <iframe
+   * mozbrowser>.
+   *
+   * <iframe mozbrowser mozapp> and <xul:browser> are not considered to be
+   * mozbrowser elements.  <iframe mozbrowser noisolation> does not count as
+   * isolated since isolation is disabled.  Isolation can only be disabled if
+   * the containing document is chrome.
    *
    * Our notion here of "contained in" means: Walk up the docshell hierarchy in
    * this process until we hit an <iframe mozapp> or <iframe mozbrowser> (or
    * until the hierarchy ends).  Return true iff the docshell we stopped on has
-   * isBrowserElement == true.
+   * isIsolatedMozBrowserElement == true.
    */
-  [infallible] readonly attribute boolean isInBrowserElement;
+  [infallible] readonly attribute boolean isInIsolatedMozBrowserElement;
 
   /**
    * Returns true if this docshell corresponds to an <iframe mozbrowser> or
diff --git a/docshell/base/nsILoadContext.idl b/docshell/base/nsILoadContext.idl
index 8daea0caa90..1523ef7318a 100644
--- a/docshell/base/nsILoadContext.idl
+++ b/docshell/base/nsILoadContext.idl
@@ -116,9 +116,13 @@ interface nsILoadContext : nsISupports
   [noscript] void SetRemoteTabs(in boolean aUseRemoteTabs);
 
   /**
-   * Returns true iff the load is occurring inside a browser element.
+   * Returns true iff the load is occurring inside an isolated mozbrowser
+   * element. <iframe mozbrowser mozapp> and <xul:browser> are not considered to
+   * be mozbrowser elements.  <iframe mozbrowser noisolation> does not count as
+   * isolated since isolation is disabled.  Isolation can only be disabled if
+   * the containing document is chrome.
    */
-  readonly attribute boolean isInBrowserElement;
+  readonly attribute boolean isInIsolatedMozBrowserElement;
 
   /**
    * Returns the app id of the app the load is occurring is in. Returns
diff --git a/dom/apps/AppsUtils.jsm b/dom/apps/AppsUtils.jsm
index c04a0c57f6b..d17c180af89 100644
--- a/dom/apps/AppsUtils.jsm
+++ b/dom/apps/AppsUtils.jsm
@@ -156,7 +156,7 @@ this.AppsUtils = {
        associatedWindow: null,
        topWindow : null,
        appId: aAppId,
-       isInBrowserElement: aInIsolatedMozBrowser,
+       isInIsolatedMozBrowserElement: aInIsolatedMozBrowser,
        originAttributes: {
          appId: aAppId,
          inIsolatedMozBrowser: aInIsolatedMozBrowser
diff --git a/dom/apps/Webapps.jsm b/dom/apps/Webapps.jsm
index 0ea7f17c60a..1d08b7dc3d7 100644
--- a/dom/apps/Webapps.jsm
+++ b/dom/apps/Webapps.jsm
@@ -3536,7 +3536,7 @@ this.DOMApplicationRegistry = {
 
       // nsILoadContext
       appId: aOldApp.installerAppId,
-      isInBrowserElement: aOldApp.installerIsBrowser,
+      isInIsolatedMozBrowserElement: aOldApp.installerIsBrowser,
       originAttributes: {
         appId: aOldApp.installerAppId,
         inIsolatedMozBrowser: aOldApp.installerIsBrowser
diff --git a/dom/browser-element/mochitest/browserElement_AudioChannel_nested.js b/dom/browser-element/mochitest/browserElement_AudioChannel_nested.js
index 226d6377ff0..611df3ef1b7 100644
--- a/dom/browser-element/mochitest/browserElement_AudioChannel_nested.js
+++ b/dom/browser-element/mochitest/browserElement_AudioChannel_nested.js
@@ -62,7 +62,7 @@ function runTests() {
 
   var context = { 'url': 'http://example.org',
                   'appId': SpecialPowers.Ci.nsIScriptSecurityManager.NO_APP_ID,
-                  'isInBrowserElement': true };
+                  'isInIsolatedMozBrowserElement': true };
   SpecialPowers.pushPermissions([
     {'type': 'browser', 'allow': 1, 'context': context},
     {'type': 'embed-apps', 'allow': 1, 'context': context}
diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index 87ba05fa411..92e7ec22eda 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -3103,7 +3103,7 @@ public:
   NS_IMETHOD GetUsePrivateBrowsing(bool*) NO_IMPL
   NS_IMETHOD SetUsePrivateBrowsing(bool) NO_IMPL
   NS_IMETHOD SetPrivateBrowsing(bool) NO_IMPL
-  NS_IMETHOD GetIsInBrowserElement(bool*) NO_IMPL
+  NS_IMETHOD GetIsInIsolatedMozBrowserElement(bool*) NO_IMPL
   NS_IMETHOD GetAppId(uint32_t*) NO_IMPL
   NS_IMETHOD GetOriginAttributes(JS::MutableHandleValue) NO_IMPL
   NS_IMETHOD GetUseRemoteTabs(bool*) NO_IMPL
diff --git a/dom/network/NetworkStatsService.jsm b/dom/network/NetworkStatsService.jsm
index eba4d70e96c..4b6d694988d 100644
--- a/dom/network/NetworkStatsService.jsm
+++ b/dom/network/NetworkStatsService.jsm
@@ -738,9 +738,9 @@ this.NetworkStatsService = {
   /*
    * Function responsible for receiving stats which are not from netd.
    */
-  saveStats: function saveStats(aAppId, aIsInBrowser, aServiceType, aNetworkInfo,
-                                aTimeStamp, aRxBytes, aTxBytes, aIsAccumulative,
-                                aCallback) {
+  saveStats: function saveStats(aAppId, aIsInIsolatedMozBrowser, aServiceType,
+                                aNetworkInfo, aTimeStamp, aRxBytes, aTxBytes,
+                                aIsAccumulative, aCallback) {
     let netId = this.convertNetworkInfo(aNetworkInfo);
     if (!netId) {
       if (aCallback) {
@@ -761,7 +761,7 @@ this.NetworkStatsService = {
     }
 
     let stats = { appId:          aAppId,
-                  isInBrowser:    aIsInBrowser,
+                  isInBrowser:    aIsInIsolatedMozBrowser,
                   serviceType:    aServiceType,
                   networkId:      this._networks[netId].network.id,
                   networkType:    this._networks[netId].network.type,
diff --git a/dom/network/NetworkStatsServiceProxy.js b/dom/network/NetworkStatsServiceProxy.js
index e7f4681e174..f3df4344dc3 100644
--- a/dom/network/NetworkStatsServiceProxy.js
+++ b/dom/network/NetworkStatsServiceProxy.js
@@ -29,7 +29,7 @@ NetworkStatsServiceProxy.prototype = {
    * Function called in the protocol layer (HTTP, FTP, WebSocket ...etc)
    * to pass the per-app stats to NetworkStatsService.
    */
-  saveAppStats: function saveAppStats(aAppId, aIsInBrowser, aNetworkInfo, aTimeStamp,
+  saveAppStats: function saveAppStats(aAppId, aIsInIsolatedMozBrowser, aNetworkInfo, aTimeStamp,
                                       aRxBytes, aTxBytes, aIsAccumulative,
                                       aCallback) {
     if (!aNetworkInfo) {
@@ -40,7 +40,7 @@ NetworkStatsServiceProxy.prototype = {
     }
 
     if (DEBUG) {
-      debug("saveAppStats: " + aAppId + " " + aIsInBrowser + " " +
+      debug("saveAppStats: " + aAppId + " " + aIsInIsolatedMozBrowser + " " +
             aNetworkInfo.type + " " + aTimeStamp + " " +
             aRxBytes + " " + aTxBytes + " " + aIsAccumulative);
     }
@@ -49,7 +49,7 @@ NetworkStatsServiceProxy.prototype = {
       aCallback = aCallback.notify;
     }
 
-    NetworkStatsService.saveStats(aAppId, aIsInBrowser, "", aNetworkInfo,
+    NetworkStatsService.saveStats(aAppId, aIsInIsolatedMozBrowser, "", aNetworkInfo,
                                   aTimeStamp, aRxBytes, aTxBytes,
                                   aIsAccumulative, aCallback);
   },
diff --git a/dom/network/interfaces/nsINetworkStatsServiceProxy.idl b/dom/network/interfaces/nsINetworkStatsServiceProxy.idl
index fba2ce9ffd9..cd6765c68a4 100644
--- a/dom/network/interfaces/nsINetworkStatsServiceProxy.idl
+++ b/dom/network/interfaces/nsINetworkStatsServiceProxy.idl
@@ -22,7 +22,12 @@ interface nsINetworkStatsServiceProxy : nsISupports
   /*
    * An interface used to record per-app traffic data.
    * @param aAppId app id
-   * @param aIsInBrowser true if the iframe element is mozbrowser
+   * @param aIsInIsolatedMozBrowser
+   *        true if the frame is an isolated mozbrowser element. <iframe
+   *        mozbrowser mozapp> and <xul:browser> are not considered to be
+   *        mozbrowser elements.  <iframe mozbrowser noisolation> does not count
+   *        as isolated since isolation is disabled.  Isolation can only be
+   *        disabled if the containing document is chrome.
    * @param aNetworkInterface network
    * @param aTimeStamp time stamp
    * @param aRxBytes received data amount
@@ -31,7 +36,7 @@ interface nsINetworkStatsServiceProxy : nsISupports
    * @param aCallback an optional callback
    */
   void saveAppStats(in unsigned long aAppId,
-                    in boolean aIsInBrowser,
+                    in boolean aIsInIsolatedMozBrowser,
                     in nsINetworkInfo aNetworkInfo,
                     in unsigned long long aTimeStamp,
                     in unsigned long long aRxBytes,
diff --git a/dom/requestsync/RequestSyncManager.js b/dom/requestsync/RequestSyncManager.js
index c5ce21e0024..d94121a6291 100644
--- a/dom/requestsync/RequestSyncManager.js
+++ b/dom/requestsync/RequestSyncManager.js
@@ -58,7 +58,7 @@ RequestSyncManager.prototype = {
     return this.sendMessage("RequestSyncManager:Registrations", {});
   },
 
-  setPolicy: function(aTask, aOrigin, aManifestURL, aIsInBrowserElement,
+  setPolicy: function(aTask, aOrigin, aManifestURL, aIsInIsolatedMozBrowserElement,
                       aState, aOverwrittenMinInterval) {
     debug('setPolicy');
 
@@ -66,19 +66,19 @@ RequestSyncManager.prototype = {
       { task: aTask,
         origin: aOrigin,
         manifestURL: aManifestURL,
-        isInBrowserElement: aIsInBrowserElement,
+        isInBrowserElement: aIsInIsolatedMozBrowserElement,
         state: aState,
         overwrittenMinInterval: aOverwrittenMinInterval });
   },
 
-  runTask: function(aTask, aOrigin, aManifestURL, aIsInBrowserElement) {
+  runTask: function(aTask, aOrigin, aManifestURL, aIsInIsolatedMozBrowserElement) {
     debug('runTask');
 
     return this.sendMessage("RequestSyncManager:RunTask",
       { task: aTask,
         origin: aOrigin,
         manifestURL: aManifestURL,
-        isInBrowserElement: aIsInBrowserElement });
+        isInBrowserElement: aIsInIsolatedMozBrowserElement });
   },
 
   registrationsResult: function(aData) {
diff --git a/extensions/cookie/test/channel_utils.js b/extensions/cookie/test/channel_utils.js
index b1678961f45..7e8e68a56a1 100644
--- a/extensions/cookie/test/channel_utils.js
+++ b/extensions/cookie/test/channel_utils.js
@@ -168,7 +168,7 @@ ChannelListener.prototype = {
  */
 function LoadContextCallback(appId, inIsolatedMozBrowser, isPrivate, isContent) {
   this.appId = appId;
-  this.isInBrowserElement = inIsolatedMozBrowser;
+  this.isInIsolatedMozBrowserElement = inIsolatedMozBrowser;
   this.usePrivateBrowsing = isPrivate;
   this.isContent = isContent;
   this.originAttributes = {
diff --git a/netwerk/base/NetStatistics.h b/netwerk/base/NetStatistics.h
index 3b91fe91572..31678a29c3b 100644
--- a/netwerk/base/NetStatistics.h
+++ b/netwerk/base/NetStatistics.h
@@ -46,13 +46,13 @@ GetActiveNetworkInfo(nsCOMPtr<nsINetworkInfo> &aNetworkInfo)
 class SaveNetworkStatsEvent : public nsRunnable {
 public:
   SaveNetworkStatsEvent(uint32_t aAppId,
-                        bool aIsInBrowser,
+                        bool aIsInIsolatedMozBrowser,
                         nsMainThreadPtrHandle<nsINetworkInfo> &aActiveNetworkInfo,
                         uint64_t aCountRecv,
                         uint64_t aCountSent,
                         bool aIsAccumulative)
     : mAppId(aAppId),
-      mIsInBrowser(aIsInBrowser),
+      mIsInIsolatedMozBrowser(aIsInIsolatedMozBrowser),
       mActiveNetworkInfo(aActiveNetworkInfo),
       mCountRecv(aCountRecv),
       mCountSent(aCountSent),
@@ -75,7 +75,7 @@ public:
 
     // save the network stats through NetworkStatsServiceProxy
     mNetworkStatsServiceProxy->SaveAppStats(mAppId,
-                                            mIsInBrowser,
+                                            mIsInIsolatedMozBrowser,
                                             mActiveNetworkInfo,
                                             PR_Now() / 1000,
                                             mCountRecv,
@@ -87,7 +87,7 @@ public:
   }
 private:
   uint32_t mAppId;
-  bool     mIsInBrowser;
+  bool     mIsInIsolatedMozBrowser;
   nsMainThreadPtrHandle<nsINetworkInfo> mActiveNetworkInfo;
   uint64_t mCountRecv;
   uint64_t mCountSent;
diff --git a/netwerk/base/PACGenerator.js b/netwerk/base/PACGenerator.js
index f41bb949833..5cb2b869c3f 100644
--- a/netwerk/base/PACGenerator.js
+++ b/netwerk/base/PACGenerator.js
@@ -107,7 +107,7 @@ PACGenerator.prototype = {
       pac += "var origins ='" + appOrigins +
              "'.split(/[ ,]+/).filter(Boolean); " +
              "if ((origins.indexOf('*') > -1 || origins.indexOf(myAppOrigin()) > -1)" +
-             " && isInBrowser()) { return 'PROXY " + proxy + "'; } ";
+             " && isInIsolatedMozBrowser()) { return 'PROXY " + proxy + "'; } ";
     }
 
     // Rules for system proxy.
diff --git a/netwerk/base/ProxyAutoConfig.cpp b/netwerk/base/ProxyAutoConfig.cpp
index deba4f8738a..6f1a2651b87 100644
--- a/netwerk/base/ProxyAutoConfig.cpp
+++ b/netwerk/base/ProxyAutoConfig.cpp
@@ -500,23 +500,24 @@ bool PACMyAppOrigin(JSContext *cx, unsigned int argc, JS::Value *vp)
   return GetRunning()->MyAppOrigin(args);
 }
 
-// IsInBrowser() javascript implementation
+// IsInIsolatedMozBrowser() javascript implementation
 static
-bool PACIsInBrowser(JSContext *cx, unsigned int argc, JS::Value *vp)
+bool PACIsInIsolatedMozBrowser(JSContext *cx, unsigned int argc, JS::Value *vp)
 {
   JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
 
   if (NS_IsMainThread()) {
-    NS_WARNING("PACIsInBrowser on Main Thread. How did that happen?");
+    NS_WARNING("PACIsInIsolatedMozBrowser on Main Thread. How did that happen?");
     return false;
   }
 
   if (!GetRunning()) {
-    NS_WARNING("PACIsInBrowser without a running ProxyAutoConfig object");
+    NS_WARNING("PACIsInIsolatedMozBrowser without a running ProxyAutoConfig"
+               "object");
     return false;
   }
 
-  return GetRunning()->IsInBrowser(args);
+  return GetRunning()->IsInIsolatedMozBrowser(args);
 }
 
 // proxyAlert(msg) javascript implementation
@@ -554,7 +555,7 @@ static const JSFunctionSpec PACGlobalFunctions[] = {
   JS_FS("myIpAddress", PACMyIpAddress, 0, 0),
   JS_FS("myAppId", PACMyAppId, 0, 0),
   JS_FS("myAppOrigin", PACMyAppOrigin, 0, 0),
-  JS_FS("isInBrowser", PACIsInBrowser, 0, 0),
+  JS_FS("isInIsolatedMozBrowser", PACIsInIsolatedMozBrowser, 0, 0),
   JS_FS("alert", PACProxyAlert, 1, 0),
   JS_FS_END
 };
@@ -636,7 +637,7 @@ private:
      * Not setting this will cause JS_CHECK_RECURSION to report false
      * positives
      */
-    JS_SetNativeStackQuota(mRuntime, 128 * sizeof(size_t) * 1024); 
+    JS_SetNativeStackQuota(mRuntime, 128 * sizeof(size_t) * 1024);
 
     JS_SetErrorReporter(mRuntime, PACErrorReporter);
 
@@ -764,7 +765,7 @@ ProxyAutoConfig::GetProxyForURI(const nsCString &aTestURI,
                                 const nsCString &aTestHost,
                                 uint32_t aAppId,
                                 const nsString &aAppOrigin,
-                                bool aIsInBrowser,
+                                bool aIsInIsolatedMozBrowser,
                                 nsACString &result)
 {
   if (mJSNeedsSetup)
@@ -783,7 +784,7 @@ ProxyAutoConfig::GetProxyForURI(const nsCString &aTestURI,
   mRunningHost = aTestHost;
   mRunningAppId = aAppId;
   mRunningAppOrigin = aAppOrigin;
-  mRunningIsInBrowser = aIsInBrowser;
+  mRunningIsInIsolatedMozBrowser = aIsInIsolatedMozBrowser;
 
   nsresult rv = NS_ERROR_FAILURE;
   JS::RootedString uriString(cx, JS_NewStringCopyZ(cx, aTestURI.get()));
@@ -865,11 +866,11 @@ ProxyAutoConfig::SrcAddress(const NetAddr *remoteAddress, nsCString &localAddres
   }
 
   PR_Close(fd);
-  
+
   char dottedDecimal[128];
   if (PR_NetAddrToString(&localName, dottedDecimal, sizeof(dottedDecimal)) != PR_SUCCESS)
     return false;
-  
+
   localAddress.Assign(dottedDecimal);
 
   return true;
@@ -947,7 +948,7 @@ ProxyAutoConfig::MyIPAddress(const JS::CallArgs &aArgs)
       rvalAssigned) {
     return rvalAssigned;
   }
-  
+
   // finally, use the old algorithm based on the local hostname
   nsAutoCString hostName;
   nsCOMPtr<nsIDNSService> dns = do_GetService(NS_DNSSERVICE_CONTRACTID);
@@ -1015,9 +1016,9 @@ ProxyAutoConfig::MyAppOrigin(const JS::CallArgs &aArgs)
 }
 
 bool
-ProxyAutoConfig::IsInBrowser(const JS::CallArgs &aArgs)
+ProxyAutoConfig::IsInIsolatedMozBrowser(const JS::CallArgs &aArgs)
 {
-  aArgs.rval().setBoolean(mRunningIsInBrowser);
+  aArgs.rval().setBoolean(mRunningIsInIsolatedMozBrowser);
   return true;
 }
 
diff --git a/netwerk/base/ProxyAutoConfig.h b/netwerk/base/ProxyAutoConfig.h
index 7f45075284a..3f89e91d640 100644
--- a/netwerk/base/ProxyAutoConfig.h
+++ b/netwerk/base/ProxyAutoConfig.h
@@ -37,7 +37,7 @@ public:
   bool     MyIPAddress(const JS::CallArgs &aArgs);
   bool     MyAppId(const JS::CallArgs &aArgs);
   bool     MyAppOrigin(const JS::CallArgs &aArgs);
-  bool     IsInBrowser(const JS::CallArgs &aArgs);
+  bool     IsInIsolatedMozBrowser(const JS::CallArgs &aArgs);
   bool     ResolveAddress(const nsCString &aHostName,
                           NetAddr *aNetAddr, unsigned int aTimeout);
 
@@ -75,8 +75,12 @@ public:
    *        The id of the app requesting connection.
    * @param aAppOrigin
    *        The origin of the app requesting connection.
-   * @param aIsInBrowser
-   *        True if the iframe has mozbrowser but has no mozapp attribute.
+   * @param aIsInIsolatedMozBrowser
+   *        True if the frame is an isolated mozbrowser element. <iframe
+   *        mozbrowser mozapp> and <xul:browser> are not considered to be
+   *        mozbrowser elements.  <iframe mozbrowser noisolation> does not count
+   *        as isolated since isolation is disabled.  Isolation can only be
+   *        disabled if the containing document is chrome.
    *
    * @param result
    *        result string as defined above.
@@ -85,7 +89,7 @@ public:
                           const nsCString &aTestHost,
                           uint32_t aAppId,
                           const nsString &aAppOrigin,
-                          bool aIsInBrowser,
+                          bool aIsInIsolatedMozBrowser,
                           nsACString &result);
 
 private:
@@ -107,7 +111,7 @@ private:
   nsCString         mRunningHost;
   uint32_t          mRunningAppId;
   nsString          mRunningAppOrigin;
-  bool              mRunningIsInBrowser;
+  bool              mRunningIsInIsolatedMozBrowser;
   nsCOMPtr<nsITimer> mTimer;
 };
 
diff --git a/netwerk/base/nsNetUtil.cpp b/netwerk/base/nsNetUtil.cpp
index aaf6ddc8df0..3576f718e98 100644
--- a/netwerk/base/nsNetUtil.cpp
+++ b/netwerk/base/nsNetUtil.cpp
@@ -559,10 +559,10 @@ NS_LoadGroupMatchesPrincipal(nsILoadGroup *aLoadGroup,
 
     // Verify load context appId and browser flag match the principal
     uint32_t contextAppId;
-    bool contextInBrowserElement;
+    bool contextInIsolatedBrowser;
     rv = loadContext->GetAppId(&contextAppId);
     NS_ENSURE_SUCCESS(rv, false);
-    rv = loadContext->GetIsInBrowserElement(&contextInBrowserElement);
+    rv = loadContext->GetIsInIsolatedMozBrowserElement(&contextInIsolatedBrowser);
     NS_ENSURE_SUCCESS(rv, false);
 
     uint32_t principalAppId;
@@ -573,7 +573,7 @@ NS_LoadGroupMatchesPrincipal(nsILoadGroup *aLoadGroup,
     NS_ENSURE_SUCCESS(rv, false);
 
     return contextAppId == principalAppId &&
-           contextInBrowserElement == principalInIsolatedBrowser;
+           contextInIsolatedBrowser == principalInIsolatedBrowser;
 }
 
 nsresult
@@ -1262,7 +1262,7 @@ NS_GetOriginAttributes(nsIChannel *aChannel,
 bool
 NS_GetAppInfo(nsIChannel *aChannel,
               uint32_t *aAppID,
-              bool *aIsInBrowserElement)
+              bool *aIsInIsolatedMozBrowserElement)
 {
     nsCOMPtr<nsILoadContext> loadContext;
     NS_QueryNotificationCallbacks(aChannel, loadContext);
@@ -1273,7 +1273,7 @@ NS_GetAppInfo(nsIChannel *aChannel,
     nsresult rv = loadContext->GetAppId(aAppID);
     NS_ENSURE_SUCCESS(rv, false);
 
-    rv = loadContext->GetIsInBrowserElement(aIsInBrowserElement);
+    rv = loadContext->GetIsInIsolatedMozBrowserElement(aIsInIsolatedMozBrowserElement);
     NS_ENSURE_SUCCESS(rv, false);
 
     return true;
diff --git a/netwerk/base/nsNetUtil.h b/netwerk/base/nsNetUtil.h
index 8174a03bd73..66b63c2a83d 100644
--- a/netwerk/base/nsNetUtil.h
+++ b/netwerk/base/nsNetUtil.h
@@ -709,12 +709,12 @@ bool NS_HasBeenCrossOrigin(nsIChannel* aChannel, bool aReport = false);
 #define NECKO_SAFEBROWSING_APP_ID UINT32_MAX - 1
 
 /**
- * Gets AppId and isInBrowserElement from channel's nsILoadContext.
+ * Gets AppId and isInIsolatedMozBrowserElement from channel's nsILoadContext.
  * Returns false if error or channel's callbacks don't implement nsILoadContext.
  */
 bool NS_GetAppInfo(nsIChannel *aChannel,
                    uint32_t *aAppID,
-                   bool *aIsInBrowserElement);
+                   bool *aIsInIsolatedMozBrowserElement);
 
 /**
  *  Gets appId and browserOnly parameters from the TOPIC_WEB_APP_CLEAR_DATA
diff --git a/netwerk/base/nsPACMan.cpp b/netwerk/base/nsPACMan.cpp
index 400b6d7953c..98b3deaaca4 100644
--- a/netwerk/base/nsPACMan.cpp
+++ b/netwerk/base/nsPACMan.cpp
@@ -237,12 +237,12 @@ private:
 //-----------------------------------------------------------------------------
 
 PendingPACQuery::PendingPACQuery(nsPACMan *pacMan, nsIURI *uri,
-                                 uint32_t appId, bool isInBrowser,
+                                 uint32_t appId, bool isInIsolatedMozBrowser,
                                  nsPACManCallback *callback,
                                  bool mainThreadResponse)
   : mPACMan(pacMan)
   , mAppId(appId)
-  , mIsInBrowser(isInBrowser)
+  , mIsInIsolatedMozBrowser(isInIsolatedMozBrowser)
   , mCallback(callback)
   , mOnMainThreadOnly(mainThreadResponse)
 {
@@ -351,7 +351,8 @@ nsPACMan::Shutdown()
 
 nsresult
 nsPACMan::AsyncGetProxyForURI(nsIURI *uri, uint32_t appId,
-                              bool isInBrowser, nsPACManCallback *callback,
+                              bool isInIsolatedMozBrowser,
+                              nsPACManCallback *callback,
                               bool mainThreadResponse)
 {
   MOZ_ASSERT(NS_IsMainThread(), "wrong thread");
@@ -364,7 +365,7 @@ nsPACMan::AsyncGetProxyForURI(nsIURI *uri, uint32_t appId,
     LoadPACFromURI(EmptyCString());
 
   RefPtr<PendingPACQuery> query =
-    new PendingPACQuery(this, uri, appId, isInBrowser, callback,
+    new PendingPACQuery(this, uri, appId, isInIsolatedMozBrowser, callback,
                         mainThreadResponse);
 
   if (IsPACURI(uri)) {
@@ -620,7 +621,7 @@ nsPACMan::ProcessPending()
   if (!completed) {
     nsresult status = mPAC.GetProxyForURI(query->mSpec, query->mHost,
                                           query->mAppId, query->mAppOrigin,
-                                          query->mIsInBrowser,
+                                          query->mIsInIsolatedMozBrowser,
                                           pacString);
     query->Complete(status, pacString);
   }
@@ -723,7 +724,7 @@ nsPACMan::AsyncOnChannelRedirect(nsIChannel *oldChannel, nsIChannel *newChannel,
                                  nsIAsyncVerifyRedirectCallback *callback)
 {
   MOZ_ASSERT(NS_IsMainThread(), "wrong thread");
-  
+
   nsresult rv = NS_OK;
   nsCOMPtr<nsIURI> pacURI;
   if (NS_FAILED((rv = newChannel->GetURI(getter_AddRefs(pacURI)))))
@@ -773,4 +774,3 @@ nsPACMan::Init(nsISystemProxySettings *systemProxySettings)
 
   return NS_OK;
 }
-
diff --git a/netwerk/base/nsPACMan.h b/netwerk/base/nsPACMan.h
index 1453550b113..7973cde27e6 100644
--- a/netwerk/base/nsPACMan.h
+++ b/netwerk/base/nsPACMan.h
@@ -55,9 +55,9 @@ class PendingPACQuery final : public nsRunnable,
 {
 public:
   PendingPACQuery(nsPACMan *pacMan, nsIURI *uri, uint32_t appId,
-                  bool isInBrowser, nsPACManCallback *callback,
+                  bool isInIsolatedMozBrowser, nsPACManCallback *callback,
                   bool mainThreadResponse);
- 
+
   // can be called from either thread
   void Complete(nsresult status, const nsCString &pacString);
   void UseAlternatePACFile(const nsCString &pacURL);
@@ -74,7 +74,7 @@ private:
 
 public:
   uint32_t                   mAppId;
-  bool                       mIsInBrowser;
+  bool                       mIsInIsolatedMozBrowser;
   nsString                   mAppOrigin;
 
 private:
@@ -108,7 +108,7 @@ public:
    * calling thread.  If the PAC file has not yet been loaded, then this method
    * will queue up the request, and complete it once the PAC file has been
    * loaded.
-   * 
+   *
    * @param uri
    *        The URI to query.
    * @param appId
diff --git a/netwerk/base/nsProtocolProxyService.cpp b/netwerk/base/nsProtocolProxyService.cpp
index d60738de5b3..693594b5a8f 100644
--- a/netwerk/base/nsProtocolProxyService.cpp
+++ b/netwerk/base/nsProtocolProxyService.cpp
@@ -104,7 +104,7 @@ public:
     NS_DECL_THREADSAFE_ISUPPORTS
 
     nsAsyncResolveRequest(nsProtocolProxyService *pps, nsIChannel *channel,
-                          uint32_t aAppId, bool aIsInBrowser,
+                          uint32_t aAppId, bool aIsInIsolatedMozBrowser,
                           uint32_t aResolveFlags,
                           nsIProtocolProxyCallback *callback)
         : mStatus(NS_OK)
@@ -114,7 +114,7 @@ public:
         , mXPComPPS(pps)
         , mChannel(channel)
         , mAppId(aAppId)
-        , mIsInBrowser(aIsInBrowser)
+        , mIsInIsolatedMozBrowser(aIsInIsolatedMozBrowser)
         , mCallback(callback)
     {
         NS_ASSERTION(mCallback, "null callback");
@@ -256,10 +256,10 @@ private:
                 // now that the load is triggered, we can resubmit the query
                 RefPtr<nsAsyncResolveRequest> newRequest =
                     new nsAsyncResolveRequest(mPPS, mChannel, mAppId,
-                                              mIsInBrowser, mResolveFlags,
+                                              mIsInIsolatedMozBrowser, mResolveFlags,
                                               mCallback);
                 rv = mPPS->mPACMan->AsyncGetProxyForURI(proxyURI, mAppId,
-                                                        mIsInBrowser,
+                                                        mIsInIsolatedMozBrowser,
                                                         newRequest,
                                                         true);
             }
@@ -299,7 +299,7 @@ private:
     nsCOMPtr<nsIProtocolProxyService>  mXPComPPS;
     nsCOMPtr<nsIChannel>               mChannel;
     uint32_t                           mAppId;
-    bool                               mIsInBrowser;
+    bool                               mIsInIsolatedMozBrowser;
     nsCOMPtr<nsIProtocolProxyCallback> mCallback;
     nsCOMPtr<nsIProxyInfo>             mProxyInfo;
 };
@@ -1261,13 +1261,13 @@ nsProtocolProxyService::AsyncResolveInternal(nsIChannel *channel, uint32_t flags
     if (NS_FAILED(rv)) return rv;
 
     uint32_t appId = NECKO_NO_APP_ID;
-    bool isInBrowser = false;
-    NS_GetAppInfo(channel, &appId, &isInBrowser);
+    bool isInIsolatedMozBrowser = false;
+    NS_GetAppInfo(channel, &appId, &isInIsolatedMozBrowser);
 
     *result = nullptr;
     RefPtr<nsAsyncResolveRequest> ctx =
-        new nsAsyncResolveRequest(this, channel, appId, isInBrowser, flags,
-                                  callback);
+        new nsAsyncResolveRequest(this, channel, appId, isInIsolatedMozBrowser,
+                                  flags, callback);
 
     nsProtocolInfo info;
     rv = GetProtocolInfo(uri, &info);
@@ -1281,7 +1281,7 @@ nsProtocolProxyService::AsyncResolveInternal(nsIChannel *channel, uint32_t flags
     // but if neither of them are in use, we can just do the work
     // right here and directly invoke the callback
 
-    rv = Resolve_Internal(channel, appId, isInBrowser, info, flags,
+    rv = Resolve_Internal(channel, appId, isInIsolatedMozBrowser, info, flags,
                           &usePACThread, getter_AddRefs(pi));
     if (NS_FAILED(rv))
         return rv;
@@ -1303,7 +1303,8 @@ nsProtocolProxyService::AsyncResolveInternal(nsIChannel *channel, uint32_t flags
 
     // else kick off a PAC thread query
 
-    rv = mPACMan->AsyncGetProxyForURI(uri, appId, isInBrowser, ctx, true);
+    rv = mPACMan->AsyncGetProxyForURI(uri, appId, isInIsolatedMozBrowser, ctx,
+                                      true);
     if (NS_SUCCEEDED(rv))
         ctx.forget(result);
     return rv;
diff --git a/netwerk/protocol/http/nsHttpTransaction.cpp b/netwerk/protocol/http/nsHttpTransaction.cpp
index e25b581d072..82ef46e6d9f 100644
--- a/netwerk/protocol/http/nsHttpTransaction.cpp
+++ b/netwerk/protocol/http/nsHttpTransaction.cpp
@@ -138,7 +138,7 @@ nsHttpTransaction::nsHttpTransaction()
     , mCountRecv(0)
     , mCountSent(0)
     , mAppId(NECKO_NO_APP_ID)
-    , mIsInBrowser(false)
+    , mIsInIsolatedMozBrowser(false)
     , mClassOfService(0)
 {
     LOG(("Creating nsHttpTransaction @%p\n", this));
@@ -248,7 +248,7 @@ nsHttpTransaction::Init(uint32_t caps,
     mChannel = do_QueryInterface(eventsink);
     nsCOMPtr<nsIChannel> channel = do_QueryInterface(eventsink);
     if (channel) {
-        NS_GetAppInfo(channel, &mAppId, &mIsInBrowser);
+        NS_GetAppInfo(channel, &mAppId, &mIsInIsolatedMozBrowser);
     }
 
 #ifdef MOZ_WIDGET_GONK
@@ -869,9 +869,9 @@ nsHttpTransaction::SaveNetworkStats(bool enforce)
     }
 
     // Create the event to save the network statistics.
-    // the event is then dispathed to the main thread.
+    // the event is then dispatched to the main thread.
     RefPtr<nsRunnable> event =
-        new SaveNetworkStatsEvent(mAppId, mIsInBrowser, mActiveNetworkInfo,
+        new SaveNetworkStatsEvent(mAppId, mIsInIsolatedMozBrowser, mActiveNetworkInfo,
                                   mCountRecv, mCountSent, false);
     NS_DispatchToMainThread(event);
 
diff --git a/netwerk/protocol/http/nsHttpTransaction.h b/netwerk/protocol/http/nsHttpTransaction.h
index ce82230ba4d..90fa9f56267 100644
--- a/netwerk/protocol/http/nsHttpTransaction.h
+++ b/netwerk/protocol/http/nsHttpTransaction.h
@@ -417,7 +417,7 @@ private:
     uint64_t                           mCountRecv;
     uint64_t                           mCountSent;
     uint32_t                           mAppId;
-    bool                               mIsInBrowser;
+    bool                               mIsInIsolatedMozBrowser;
 #ifdef MOZ_WIDGET_GONK
     nsMainThreadPtrHandle<nsINetworkInfo> mActiveNetworkInfo;
 #endif
diff --git a/netwerk/protocol/websocket/WebSocketChannel.cpp b/netwerk/protocol/websocket/WebSocketChannel.cpp
index ee190fcc85f..79ac5447071 100644
--- a/netwerk/protocol/websocket/WebSocketChannel.cpp
+++ b/netwerk/protocol/websocket/WebSocketChannel.cpp
@@ -1176,7 +1176,7 @@ WebSocketChannel::WebSocketChannel() :
   mCountRecv(0),
   mCountSent(0),
   mAppId(NECKO_NO_APP_ID),
-  mIsInBrowser(false)
+  mIsInIsolatedMozBrowser(false)
 {
   MOZ_ASSERT(NS_IsMainThread(), "not main thread");
 
@@ -1388,7 +1388,7 @@ WebSocketChannel::BeginOpenInternal()
   }
 
   if (localChannel) {
-    NS_GetAppInfo(localChannel, &mAppId, &mIsInBrowser);
+    NS_GetAppInfo(localChannel, &mAppId, &mIsInIsolatedMozBrowser);
   }
 
 #ifdef MOZ_WIDGET_GONK
@@ -3909,9 +3909,9 @@ WebSocketChannel::SaveNetworkStats(bool enforce)
   }
 
   // Create the event to save the network statistics.
-  // the event is then dispathed to the main thread.
+  // the event is then dispatched to the main thread.
   RefPtr<nsRunnable> event =
-    new SaveNetworkStatsEvent(mAppId, mIsInBrowser, mActiveNetworkInfo,
+    new SaveNetworkStatsEvent(mAppId, mIsInIsolatedMozBrowser, mActiveNetworkInfo,
                               countRecv, countSent, false);
   NS_DispatchToMainThread(event);
 
diff --git a/netwerk/protocol/websocket/WebSocketChannel.h b/netwerk/protocol/websocket/WebSocketChannel.h
index de9fed7064c..fe67b3ab5ce 100644
--- a/netwerk/protocol/websocket/WebSocketChannel.h
+++ b/netwerk/protocol/websocket/WebSocketChannel.h
@@ -300,7 +300,7 @@ private:
   Atomic<uint64_t, Relaxed>       mCountRecv;
   Atomic<uint64_t, Relaxed>       mCountSent;
   uint32_t                        mAppId;
-  bool                            mIsInBrowser;
+  bool                            mIsInIsolatedMozBrowser;
 #ifdef MOZ_WIDGET_GONK
   nsMainThreadPtrHandle<nsINetworkInfo> mActiveNetworkInfo;
 #endif
diff --git a/netwerk/test/unit/head_channels.js b/netwerk/test/unit/head_channels.js
index bd259c27635..68db0b9ca8e 100644
--- a/netwerk/test/unit/head_channels.js
+++ b/netwerk/test/unit/head_channels.js
@@ -210,7 +210,7 @@ ChannelEventSink.prototype = {
  */
 function LoadContextCallback(appId, inIsolatedMozBrowser, isPrivate, isContent) {
   this.appId = appId;
-  this.isInBrowserElement = inIsolatedMozBrowser;
+  this.isInIsolatedMozBrowserElement = inIsolatedMozBrowser;
   this.originAttributes = {
     appId: appId,
     inIsolatedMozBrowser: inIsolatedMozBrowser
@@ -239,4 +239,3 @@ LoadContextCallback.prototype = {
     throw Cr.NS_ERROR_NO_INTERFACE;
   },
 }
-
diff --git a/netwerk/test/unit/test_cache_jar.js b/netwerk/test/unit/test_cache_jar.js
index 3010a74bb3d..d84ef2f884a 100644
--- a/netwerk/test/unit/test_cache_jar.js
+++ b/netwerk/test/unit/test_cache_jar.js
@@ -24,7 +24,7 @@ function makeChan(url, appId, inIsolatedMozBrowser) {
                     .QueryInterface(Ci.nsIHttpChannel);
   chan.notificationCallbacks = {
     appId: appId,
-    isInBrowserElement: inIsolatedMozBrowser,
+    isInIsolatedMozBrowserElement: inIsolatedMozBrowser,
     originAttributes: {
       appId: appId,
       inIsolatedMozBrowser: inIsolatedMozBrowser,
@@ -98,7 +98,7 @@ function run_test() {
 function doneFirstLoad(req, buffer, expected) {
   // Load it again, make sure it hits the cache
   var nc = req.notificationCallbacks.getInterface(Ci.nsILoadContext);
-  var chan = makeChan(URL, nc.appId, nc.isInBrowserElement);
+  var chan = makeChan(URL, nc.appId, nc.isInIsolatedMozBrowserElement);
   chan.asyncOpen2(new ChannelListener(doneSecondLoad, expected));
 }
 
diff --git a/netwerk/test/unit/test_protocolproxyservice.js b/netwerk/test/unit/test_protocolproxyservice.js
index da7ef7f8bbd..b8fd682e027 100644
--- a/netwerk/test/unit/test_protocolproxyservice.js
+++ b/netwerk/test/unit/test_protocolproxyservice.js
@@ -568,7 +568,7 @@ function run_pac3_test() {
 
 function run_pac4_test() {
   var appId = 10;
-  var isInBrowser = true;
+  var isInIsolatedMozBrowser = true;
   var appOrigin = "apps://browser.gaiamobile.com";
 
   // We have to setup a profile, otherwise indexed db used by webapps
@@ -589,7 +589,7 @@ function run_pac4_test() {
   var pac = 'data:text/plain,' +
             'function FindProxyForURL(url, host) {' +
             ' if (myAppId() == ' + appId +
-            ' && isInBrowser() == ' + isInBrowser +
+            ' && isInIsolatedMozBrowser() == ' + isInIsolatedMozBrowser +
             ' && myAppOrigin() == "' + appOrigin + '")' +
             '   return "PROXY foopy:8080; DIRECT";' +
             '}';
@@ -598,7 +598,7 @@ function run_pac4_test() {
     loadUsingSystemPrincipal: true
   });
   channel.notificationCallbacks =
-    AppsUtils.createLoadContext(appId, isInBrowser);
+    AppsUtils.createLoadContext(appId, isInIsolatedMozBrowser);
 
   // Configure PAC
   prefs.setIntPref("network.proxy.type", 2);
@@ -745,7 +745,7 @@ function host_filters_1()
   uriStrUseProxyList = [ "http://www.mozilla.com/",
                              "http://mail.google.com/",
                              "http://somehost.domain.co.uk/",
-                             "http://somelocalhost/" ];  
+                             "http://somelocalhost/" ];
   check_host_filters(uriStrUseProxyList, false, host_filters_2);
 }
 
@@ -769,7 +769,7 @@ function host_filters_4()
 {
   // Cleanup
   prefs.setCharPref("network.proxy.no_proxies_on", "");
-  do_check_eq(prefs.getCharPref("network.proxy.no_proxies_on"), "");  
+  do_check_eq(prefs.getCharPref("network.proxy.no_proxies_on"), "");
 
   run_myipaddress_test();
 }
@@ -811,7 +811,7 @@ function myipaddress_callback(pi)
   do_check_neq(pi.host, null);
   do_check_neq(pi.host, "127.0.0.1");
   do_check_neq(pi.host, "::1");
-  
+
   run_myipaddress_test_2();
 }
 
@@ -849,7 +849,7 @@ function myipaddress2_callback(pi)
   do_check_neq(pi.host, null);
   do_check_neq(pi.host, "127.0.0.1");
   do_check_neq(pi.host, "::1");
-  
+
   run_failed_script_test();
 }
 
diff --git a/netwerk/test/unit_ipc/child_app_offline.js b/netwerk/test/unit_ipc/child_app_offline.js
index 987291f7db7..26128586f32 100644
--- a/netwerk/test/unit_ipc/child_app_offline.js
+++ b/netwerk/test/unit_ipc/child_app_offline.js
@@ -11,7 +11,7 @@ function makeChan(url, appId, inIsolatedMozBrowser) {
                     .QueryInterface(Ci.nsIHttpChannel);
   chan.notificationCallbacks = {
     appId: appId,
-    isInBrowserElement: inIsolatedMozBrowser,
+    isInIsolatedMozBrowserElement: inIsolatedMozBrowser,
     originAttributes: {
       appId: appId,
       inIsolatedMozBrowser: inIsolatedMozBrowser,
diff --git a/uriloader/prefetch/OfflineCacheUpdateParent.cpp b/uriloader/prefetch/OfflineCacheUpdateParent.cpp
index a603ea6ea2e..5c40320fd33 100644
--- a/uriloader/prefetch/OfflineCacheUpdateParent.cpp
+++ b/uriloader/prefetch/OfflineCacheUpdateParent.cpp
@@ -259,10 +259,10 @@ OfflineCacheUpdateParent::SetRemoteTabs(bool aUseRemoteTabs)
 }
 
 NS_IMETHODIMP
-OfflineCacheUpdateParent::GetIsInBrowserElement(bool *aIsInBrowserElement)
+OfflineCacheUpdateParent::GetIsInIsolatedMozBrowserElement(bool *aIsInIsolatedMozBrowserElement)
 {
     NS_ENSURE_TRUE(mLoadingPrincipal, NS_ERROR_UNEXPECTED);
-    return mLoadingPrincipal->GetIsInIsolatedMozBrowserElement(aIsInBrowserElement);
+    return mLoadingPrincipal->GetIsInIsolatedMozBrowserElement(aIsInIsolatedMozBrowserElement);
 }
 
 NS_IMETHODIMP