Fix for bug 490592 (Possible to GC way too much during shutdown due to XUL and XBL prototypes). r/sr=bz.

content/xbl/src/nsXBLDocumentInfo.cpp

@@ -265,6 +265,7 @@ nsXBLDocGlobalObject::SetContext(nsIScriptContext *aScriptContext)
   nsresult rv;
   rv = aScriptContext->InitContext(nsnull);
   NS_WARN_IF_FALSE(NS_SUCCEEDED(rv), "Script Language's InitContext failed");
+  aScriptContext->SetGCOnDestruction(PR_FALSE);
   aScriptContext->DidInitializeContext();
   // and we set up our global manually
   mScriptContext = aScriptContext;

content/xul/document/src/nsXULPrototypeDocument.cpp

@@ -693,6 +693,7 @@ nsXULPDGlobalObject::SetScriptContext(PRUint32 lang_id, nsIScriptContext *aScrip
   void *script_glob = nsnull;
 
   if (aScriptContext) {
+    aScriptContext->SetGCOnDestruction(PR_FALSE);
     aScriptContext->DidInitializeContext();
     script_glob = aScriptContext->GetNativeGlobal();
     NS_ASSERTION(script_glob, "GetNativeGlobal returned NULL!");

dom/base/nsDOMScriptObjectFactory.cpp

@@ -278,21 +278,6 @@ nsDOMScriptObjectFactory::Observe(nsISupports *aSubject,
       cache->Flush();
 #endif
 
-    nsCOMPtr<nsIThreadJSContextStack> stack =
-      do_GetService("@mozilla.org/js/xpc/ContextStack;1");
-
-    if (stack) {
-      JSContext *cx = nsnull;
-
-      stack->GetSafeJSContext(&cx);
-
-      if (cx) {
-        // Do one final GC to clean things up before shutdown.
-
-        ::JS_GC(cx);
-      }
-    }
-
     nsGlobalWindow::ShutDown();
     nsDOMClassInfo::ShutDown();
 

js/src/xpconnect/loader/mozJSComponentLoader.cpp

@@ -1674,8 +1674,6 @@ mozJSComponentLoader::Observe(nsISupports *subject, const char *topic,
             mFastLoadTimer->Cancel();
         }
 
-        JS_GC(mContext);
-
         CloseFastLoad();
     }
     else if (!strcmp(topic, "xpcom-shutdown-loaders")) {