[worklets] Add stub classes for window.animationWorklet

third_party/WebKit/Source/core/workers/WorkletGlobalScopeProxy.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WorkletGlobalScopeProxy_h
 #define WorkletGlobalScopeProxy_h
 
 #include "core/CoreExport.h"
+#include "platform/weborigin/KURL.h"
+#include "wtf/text/WTFString.h"
 
 namespace blink {
 
 // A proxy to talk to the worklet global scope. The global scope may exist in
 // the main thread or on a different thread.
 class CORE_EXPORT WorkletGlobalScopeProxy {
 public:
     virtual ~WorkletGlobalScopeProxy() { }
 
     virtual void evaluateScript(const String& source, const KURL& scriptURL) = 0;
     virtual void terminateWorkletGlobalScope() = 0;
 };
 
 } // namespace blink
 
 #endif // WorkletGlobalScopeProxy_h