Break dependency between ChromeClient and WebViewImpl, and ChromeClientImpl.

third_party/WebKit/Source/core/exported/WebViewBase.h

 // Copyright 2017 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 WebViewBase_h
 
 #ifndef WebViewBase_h
 #define WebViewBase_h
 
 #include "platform/transforms/TransformationMatrix.h"
 #include "platform/wtf/RefCounted.h"
 #include "public/platform/WebDisplayMode.h"
 #include "public/platform/WebInputEventResult.h"
 #include "public/web/WebElement.h"
 #include "public/web/WebView.h"
 
 namespace blink {
 
 class AnimationWorkletProxyClient;
+class ChromeClient;
 class CompositorAnimationHost;
 class CompositorWorkerProxyClient;
 class CompositorAnimationTimeline;
 class ContextMenuProvider;
 class DevToolsEmulator;
 class Frame;
 class GraphicsLayer;
 class HitTestResult;
 class Page;
 class PaintLayerCompositor;
@@ skipping 138 matching lines @@
   // root.
   virtual WebInputMethodControllerImpl* GetActiveWebInputMethodController()
       const = 0;
   virtual void ScheduleAnimationForWidget() = 0;
   virtual CompositorWorkerProxyClient* CreateCompositorWorkerProxyClient() = 0;
   virtual AnimationWorkletProxyClient* CreateAnimationWorkletProxyClient() = 0;
   virtual void SetRootGraphicsLayer(GraphicsLayer*) = 0;
   virtual void SetRootLayer(WebLayer*) = 0;
   virtual CompositorAnimationHost* AnimationHost() const = 0;
   virtual HitTestResult CoreHitTestResultAt(const WebPoint&) = 0;
+
+  virtual class ChromeClient& ChromeClient() const = 0;
 };
 }
 
 #endif