Make DOMWrapperWorld::current() callable from workers

Source/bindings/v8/DOMWrapperWorld.h

Index: Source/bindings/v8/DOMWrapperWorld.h
diff --git a/Source/bindings/v8/DOMWrapperWorld.h b/Source/bindings/v8/DOMWrapperWorld.h
index 17f23ffdc9e8fbf0a537a457fa62a43b9054ce9d..00abab7aac70ee154a863336e81ea347d6bce7fb 100644
--- a/Source/bindings/v8/DOMWrapperWorld.h
+++ b/Source/bindings/v8/DOMWrapperWorld.h
@@ -34,11 +34,12 @@
 #include "bindings/v8/V8DOMActivityLogger.h"
 #include "bindings/v8/V8PerContextData.h"
 #include "platform/weborigin/SecurityOrigin.h"
-#include <v8.h>
+#include "wtf/MainThread.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/WTFString.h"
+#include <v8.h>
 
 namespace WebCore {
 
@@ -68,12 +69,24 @@ public:
 
     static DOMWrapperWorld* world(v8::Handle<v8::Context> context)
     {
-        ASSERT(contextHasCorrectPrototype(context));

[dcarney, 2014/02/27 17:03:44]

This ASSERT has saved us a lot of debugging in the past.  It would be nice not
to lose it.

[haraken, 2014/02/28 00:06:25]

Done. Reverted back the ASSERT.

-        return V8PerContextDataHolder::from(context)->world();
+        V8PerContextDataHolder* contextHolder = V8PerContextDataHolder::from(context);
+        return contextHolder ? contextHolder->world() : 0;
     }
 
     // Will return null if there is no DOMWrapperWorld for the current v8::Context
-    static DOMWrapperWorld* current(v8::Isolate*);
+    static DOMWrapperWorld* current(v8::Isolate* isolate)
+    {
+        v8::Handle<v8::Context> context = isolate->GetCurrentContext();
+        if (context.IsEmpty()) {
+            // It's possible that DOMWrapperWorld::current() is called while window is being initialized.
+            // To make DOMWrapperWorld::current() workable during the initialization phase,
+            // we cache the world of the initializing window on worldOfInitializingWindow.
+            // If there is no initiazing window, worldOfInitializingWindow is 0.
+            return worldOfInitializingWindow;
+        }
+        return world(context);
+    }
+
     static DOMWrapperWorld* mainWorld();
 
     // Associates an isolated world (see above for description) with a security
@@ -108,11 +121,17 @@ public:
     int extensionGroup() const { return m_extensionGroup; }
     DOMDataStore& domDataStore() { return *m_domDataStore; }
 
-private:
-    static unsigned isolatedWorldCount;
+    static void setWorldOfInitializingWindow(DOMWrapperWorld* world)
+    {
+        ASSERT(isMainThread());
+        worldOfInitializingWindow = world;
+    }
 
+private:
     DOMWrapperWorld(int worldId, int extensionGroup);
-    static bool contextHasCorrectPrototype(v8::Handle<v8::Context>);
+
+    static unsigned isolatedWorldCount;
+    static DOMWrapperWorld* worldOfInitializingWindow;
 
     const int m_worldId;
     const int m_extensionGroup;