bindings: Add empty checks for toV8()

Source/bindings/core/v8/V8CustomElementLifecycleCallbacks.cpp

Index: Source/bindings/core/v8/V8CustomElementLifecycleCallbacks.cpp
diff --git a/Source/bindings/core/v8/V8CustomElementLifecycleCallbacks.cpp b/Source/bindings/core/v8/V8CustomElementLifecycleCallbacks.cpp
index 851eba6315cd5aa72d207ee7bf8a39b10ce730ae..7d54e1c9216c0d920604605f276b0330ac59ad6c 100644
--- a/Source/bindings/core/v8/V8CustomElementLifecycleCallbacks.cpp
+++ b/Source/bindings/core/v8/V8CustomElementLifecycleCallbacks.cpp
@@ -156,6 +156,8 @@ void V8CustomElementLifecycleCallbacks::created(Element* element)
     v8::Local<v8::Object> receiver = m_scriptState->world().domDataStore().get(element, isolate);
     if (receiver.IsEmpty())
         receiver = toV8(element, context->Global(), isolate).As<v8::Object>();
+    if (receiver.IsEmpty())
+        return;

[haraken, 2015/04/28 04:24:59]

Not related to your CL, this code is doing something strange. A common patter
would be:

  receiver = DOMDataStore::getWrapper();
  if (receiver.isEmpty())
    receiver = wrap();
  ...

[Yuki, 2015/04/28 04:47:57]

and it should be done inside toV8().

I agree that the current code is faster than a simple call to toV8 because it
already knew the |world| and there is no need to look up the |world|, though.

[bashi, 2015/04/28 05:41:53]

As chatted offline, we can simply use toV8(). Done.

 
     // Swizzle the prototype of the wrapper.
     v8::Local<v8::Object> prototype = m_prototype.newLocal(isolate);
@@ -197,7 +199,8 @@ void V8CustomElementLifecycleCallbacks::attributeChanged(Element* element, const
     v8::Isolate* isolate = m_scriptState->isolate();
     v8::Local<v8::Context> context = m_scriptState->context();
     v8::Local<v8::Object> receiver = toV8(element, context->Global(), isolate).As<v8::Object>();
-    ASSERT(!receiver.IsEmpty());
+    if (receiver.IsEmpty())
+        return;
 
     v8::Local<v8::Function> callback = m_attributeChanged.newLocal(isolate);
     if (callback.IsEmpty())
@@ -232,7 +235,8 @@ void V8CustomElementLifecycleCallbacks::call(const ScopedPersistent<v8::Function
         return;
 
     v8::Local<v8::Object> receiver = toV8(element, context->Global(), isolate).As<v8::Object>();
-    ASSERT(!receiver.IsEmpty());
+    if (receiver.IsEmpty())

[haraken, 2015/04/28 04:24:59]

Ditto. A bit too late to check the emptiness.

[bashi, 2015/04/28 05:41:53]

Done.

+        return;
 
     v8::TryCatch exceptionCatcher;
     exceptionCatcher.SetVerbose(true);