Add CHECKs in WindowProxy initialization/detach to enforce invariants

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

 /*
  * Copyright (C) 2008, 2009, 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
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 42 matching lines @@
     : WindowProxy(isolate, frame, std::move(world)) {}
 
 void RemoteWindowProxy::disposeContext(GlobalDetachmentBehavior behavior) {
   if (m_lifecycle != Lifecycle::ContextInitialized)
     return;
 
   if (behavior == DetachGlobal) {
     v8::Local<v8::Context> context = m_scriptState->context();
     // Clean up state on the global proxy, which will be reused.
     if (!m_globalProxy.isEmpty()) {
-      // TODO(yukishiino): This DCHECK failed on Canary (M57) and Dev (M56).
-      // We need to figure out why m_globalProxy != context->Global().
-      DCHECK(m_globalProxy == context->Global());
-      DCHECK_EQ(toScriptWrappable(context->Global()),
-                toScriptWrappable(
-                    context->Global()->GetPrototype().As<v8::Object>()));
+      CHECK(m_globalProxy == context->Global());
+      CHECK_EQ(toScriptWrappable(context->Global()),
+               toScriptWrappable(
+                   context->Global()->GetPrototype().As<v8::Object>()));
       m_globalProxy.get().SetWrapperClassId(0);
     }
     V8DOMWrapper::clearNativeInfo(isolate(), context->Global());
     m_scriptState->detachGlobalObject();
 
 #if DCHECK_IS_ON()
     didDetachGlobalObject();
 #endif
   }
 
@@ skipping 94 matching lines @@
 
   // The named properties object of Window interface.
   v8::Local<v8::Object> windowProperties =
       windowPrototype->GetPrototype().As<v8::Object>();
   CHECK(!windowProperties.IsEmpty());
   V8DOMWrapper::setNativeInfo(isolate(), windowProperties, wrapperTypeInfo,
                               window);
 }
 
 }  // namespace blink