Always check that a Name is a String before converting it.

third_party/WebKit/Source/bindings/core/v8/WindowProxy.cpp

Index: third_party/WebKit/Source/bindings/core/v8/WindowProxy.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/WindowProxy.cpp b/third_party/WebKit/Source/bindings/core/v8/WindowProxy.cpp
index 37112f469bea8e21df331bce5ab2808ebb3fcbe7..ae45713e008b0b2fd6407d1e148676c8c8f4a46c 100644
--- a/third_party/WebKit/Source/bindings/core/v8/WindowProxy.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/WindowProxy.cpp
@@ -529,6 +529,8 @@ static v8::Local<v8::Value> getNamedProperty(HTMLDocument* htmlDocument, const A
 
 static void getter(v8::Local<v8::Name> property, const v8::PropertyCallbackInfo<v8::Value>& info)
 {
+    if (!property->IsString())
+        return;
     // FIXME: Consider passing StringImpl directly.
     AtomicString name = toCoreAtomicString(property.As<v8::String>());
     HTMLDocument* htmlDocument = V8HTMLDocument::toImpl(info.Holder());