Break dependency between ChromeClient and WebViewImpl, and ChromeClientImpl.

third_party/WebKit/Source/web/ChromeClientImpl.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * 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.
@@ skipping 211 matching lines @@
 
   void DidObserveNonGetFetchFromScript() const override;
 
   std::unique_ptr<WebFrameScheduler> CreateFrameScheduler(
       BlameContext*) override;
 
   double LastFrameTimeMonotonic() const override;
 
   void RegisterPopupOpeningObserver(PopupOpeningObserver*) override;
   void UnregisterPopupOpeningObserver(PopupOpeningObserver*) override;
-  void NotifyPopupOpeningObservers() const;
+  void NotifyPopupOpeningObservers() const override;
 
   void InstallSupplements(LocalFrame&) override;
 
   WebLayerTreeView* GetWebLayerTreeView(LocalFrame*) override;
 
  private:
   explicit ChromeClientImpl(WebViewBase*);
 
   bool IsChromeClientImpl() const override { return true; }
 
   void SetCursor(const WebCursorInfo&, LocalFrame*);
 
   WebViewBase* web_view_;  // Weak pointer.
   WindowFeatures window_features_;
   Vector<PopupOpeningObserver*> popup_opening_observers_;
   Cursor last_set_mouse_cursor_for_testing_;
   bool cursor_overridden_;
   bool did_request_non_empty_tool_tip_;
 };
 
 DEFINE_TYPE_CASTS(ChromeClientImpl,
                   ChromeClient,
                   client,
                   client->IsChromeClientImpl(),
                   client.IsChromeClientImpl());
 
 }  // namespace blink
 
 #endif