Ensure that we can repeatedly set an expando on a plugin object

third_party/WebKit/Source/bindings/core/v8/custom/V8HTMLPlugInElementCustom.cpp

Index: third_party/WebKit/Source/bindings/core/v8/custom/V8HTMLPlugInElementCustom.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/custom/V8HTMLPlugInElementCustom.cpp b/third_party/WebKit/Source/bindings/core/v8/custom/V8HTMLPlugInElementCustom.cpp
index 1c60662c05a1535f9d58a73be1ab03851a21bf90..0bd54b57b921bab2b278fb610c127e42a1602418 100644
--- a/third_party/WebKit/Source/bindings/core/v8/custom/V8HTMLPlugInElementCustom.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/custom/V8HTMLPlugInElementCustom.cpp
@@ -74,11 +74,6 @@ void setScriptableObjectProperty(
     v8::Local<v8::Value> value,
     const v8::PropertyCallbackInfo<v8::Value>& info) {
   ASSERT(!value.IsEmpty());
-  // Don't intercept any of the properties of the HTMLPluginElement.
-  v8::Local<v8::String> v8Name = v8String(info.GetIsolate(), name);
-  if (v8CallBoolean(
-          info.Holder()->Has(info.GetIsolate()->GetCurrentContext(), v8Name)))
-    return;
 
   HTMLPlugInElement* impl = ElementType::toImpl(info.Holder());
   RefPtr<SharedPersistent<v8::Object>> wrapper = impl->pluginWrapper();
@@ -90,6 +85,15 @@ void setScriptableObjectProperty(
   if (instance.IsEmpty())
     return;
 
+  // Don't intercept any of the properties of the HTMLPluginElement.
+  v8::Local<v8::String> v8Name = v8String(info.GetIsolate(), name);
+  if (!v8CallBoolean(instance->HasOwnProperty(
+          info.GetIsolate()->GetCurrentContext(), v8Name)) &&
+      v8CallBoolean(
+          info.Holder()->Has(info.GetIsolate()->GetCurrentContext(), v8Name))) {
+    return;
+  }
+
   // FIXME: The gTalk pepper plugin is the only plugin to make use of
   // SetProperty and that is being deprecated. This can be removed as soon as
   // it goes away.