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

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

Index: Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp
diff --git a/Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp b/Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp
index b43dace9a5bbdcf09199b2a4d0ea04b6f89552b9..687473e47b45ce1300a75c6d9647f9eb88a9aad3 100644
--- a/Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp
+++ b/Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp
@@ -199,9 +199,23 @@ void V8CSSStyleDeclaration::namedPropertyGetterCustom(v8::Local<v8::Name> name,
 {
     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());