Move asserts for tracking global object detachment to WindowProxy.

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

Index: third_party/WebKit/Source/bindings/core/v8/RemoteWindowProxy.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/RemoteWindowProxy.cpp b/third_party/WebKit/Source/bindings/core/v8/RemoteWindowProxy.cpp
index f3948344c3cb9617d6f8a42aa3dc9147bcf85006..8363a820be859a2ca0c4e6d45bc3ac57b157ccef 100644
--- a/third_party/WebKit/Source/bindings/core/v8/RemoteWindowProxy.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/RemoteWindowProxy.cpp
@@ -70,6 +70,10 @@ void RemoteWindowProxy::disposeContext(GlobalDetachmentBehavior behavior) {
     }
     V8DOMWrapper::clearNativeInfo(isolate(), context->Global());
     m_scriptState->detachGlobalObject();
+
+#if DCHECK_IS_ON()
+    didDetachGlobalProxy();
+#endif
   }
 
   m_scriptState->disposePerContextData();
@@ -150,6 +154,10 @@ void RemoteWindowProxy::setupWindowPrototypeChain() {
   // reference to the DOMWindow.
   m_globalProxy.get().SetWrapperClassId(wrapperTypeInfo->wrapperClassId);
 
+#if DCHECK_IS_ON()
+  didAttachGlobalProxy();
+#endif
+
   // The global object, aka window wrapper object.
   v8::Local<v8::Object> windowWrapper =
       globalProxy->GetPrototype().As<v8::Object>();