bindings: Adds check for attributes on prototype chains in CSSStyleDeclaration.

Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp

 /*
  * Copyright (C) 2007-2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
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@@ skipping 181 matching lines @@
     if (cssPropertyInfo(v8Name.As<v8::String>(), info.GetIsolate())) {
         v8SetReturnValueInt(info, 0);
         return;
     }
 }
 
 void V8CSSStyleDeclaration::namedPropertyGetterCustom(v8::Local<v8::Name> name, const v8::PropertyCallbackInfo<v8::Value>& info)
 {
     if (!name->IsString())
         return;
+    auto nameString = name.As<v8::String>();
+    auto context = info.GetIsolate()->GetCurrentContext();
     // First look for API defined attributes on the style declaration object.
-    if (v8CallBoolean(info.Holder()->HasRealNamedCallbackProperty(info.GetIsolate()->GetCurrentContext(), name.As<v8::String>())))
+    if (v8CallBoolean(info.Holder()->HasRealNamedCallbackProperty(context, nameString)))
         return;
+    {
+        v8::Local<v8::Value> returnValue;
+        v8::TryCatch tryCatch;
+        if (v8Call(info.Holder()->GetRealNamedPropertyInPrototypeChain(context, nameString), returnValue, tryCatch)) {

[bashi, 2015/04/07 08:44:56]

I read the following comment on GetRealNamedPropertyInPrototypeChain() as "V8
API could return an empty maybe handle without exception". @dcarney, is this
correct?

"If result.IsEmpty() no real property was located in the prototype chain."

v8Call() assumes that there must be an exception if result.IsEmpty() is true, so
we can't use v8Call() here. Maybe just use ToLocal()?

[Yuki, 2015/04/07 09:29:00]

I think that it is an intended behavior that
GetRealNamedPropertyInPrototypeChain returns an empty handle if no property
found.  The old version has the same spec.  Having said that, I agree that this
is confusing.

Fixed to not use v8Call.

+            v8SetReturnValue(info, returnValue);
+            return;
+        }
+        if (tryCatch.HasCaught()) {
+            tryCatch.ReThrow();
+            return;
+        }
+    }
 
     // Search the style declaration.
     CSSPropertyInfo* propInfo = cssPropertyInfo(name.As<v8::String>(), info.GetIsolate());
 
     // Do not handle non-property names.
     if (!propInfo)
         return;
 
     CSSStyleDeclaration* impl = V8CSSStyleDeclaration::toImpl(info.Holder());
     RefPtrWillBeRawPtr<CSSValue> cssValue = impl->getPropertyCSSValueInternal(static_cast<CSSPropertyID>(propInfo->propID));
@@ skipping 19 matching lines @@
     ExceptionState exceptionState(ExceptionState::SetterContext, getPropertyName(static_cast<CSSPropertyID>(propInfo->propID)), "CSSStyleDeclaration", info.Holder(), info.GetIsolate());
     impl->setPropertyInternal(static_cast<CSSPropertyID>(propInfo->propID), propertyValue, false, exceptionState);
 
     if (exceptionState.throwIfNeeded())
         return;
 
     v8SetReturnValue(info, value);
 }
 
 } // namespace blink