Reland of Call EnsureWebKitInitialized() before registering extensions

extensions/renderer/dispatcher.cc

Index: extensions/renderer/dispatcher.cc
diff --git a/extensions/renderer/dispatcher.cc b/extensions/renderer/dispatcher.cc
index 4351b22cc2bff7341a700543ea31b98dc910c69f..4d6dd9729e31d0b93e8d01cdece068664d021d16 100644
--- a/extensions/renderer/dispatcher.cc
+++ b/extensions/renderer/dispatcher.cc
@@ -199,8 +199,6 @@
         kInitialExtensionIdleHandlerDelayMs);
   }
 
-  RenderThread::Get()->RegisterExtension(SafeBuiltins::CreateV8Extension());
-
   script_context_set_.reset(
       new ScriptContextSet(&extensions_, &active_extension_ids_));
   user_script_set_manager_.reset(new UserScriptSetManager(&extensions_));
@@ -744,6 +742,8 @@
 }
 
 void Dispatcher::WebKitInitialized() {
+  RenderThread::Get()->RegisterExtension(SafeBuiltins::CreateV8Extension());
+
   // For extensions, we want to ensure we call the IdleHandler every so often,
   // even if the extension keeps up activity.
   if (set_idle_notifications_) {