Introduce the abstract class WebViewBase, to decouple WebViewImpl.

third_party/WebKit/Source/web/WebFrameWidgetBase.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 WebFrameWidgetBase_h
 #define WebFrameWidgetBase_h
 
 #include "core/clipboard/DataObject.h"
 #include "platform/UserGestureIndicator.h"
 #include "platform/wtf/Assertions.h"
 #include "public/platform/WebDragData.h"
 #include "public/web/WebFrameWidget.h"
 
 namespace blink {
 
 class AnimationWorkletProxyClient;
 class CompositorAnimationHost;
 class CompositorWorkerProxyClient;
 class GraphicsLayer;
 class WebImage;
 class WebLayer;
 class WebLayerTreeView;
-class WebViewImpl;
+class WebViewBase;
 class HitTestResult;
 struct WebPoint;
 
 class WebFrameWidgetBase : public WebFrameWidget {
  public:
   virtual bool ForSubframe() const = 0;
   virtual void ScheduleAnimation() = 0;
   virtual CompositorWorkerProxyClient* CreateCompositorWorkerProxyClient() = 0;
   virtual AnimationWorkletProxyClient* CreateAnimationWorkletProxyClient() = 0;
   virtual WebWidgetClient* Client() const = 0;
@@ skipping 54 matching lines @@
   // updating a drag over a target. If we're starting a drag, |isEntering|
   // should be true.
   WebDragOperation DragTargetDragEnterOrOver(const WebPoint& point_in_viewport,
                                              const WebPoint& screen_point,
                                              DragAction,
                                              int modifiers);
 
   // Helper function to call VisualViewport::viewportToRootFrame().
   WebPoint ViewportToRootFrame(const WebPoint& point_in_viewport) const;
 
-  WebViewImpl* View() const;
+  WebViewBase* View() const;
 
   // Returns the page object associated with this widget. This may be null when
   // the page is shutting down, but will be valid at all other times.
   Page* GetPage() const;
 
   // A copy of the web drop data object we received from the browser.
   Persistent<DataObject> current_drag_data_;
 
   bool doing_drag_and_drop_ = false;
 
@@ skipping 15 matching lines @@
   RefPtr<UserGestureToken> pointer_lock_gesture_token_;
 
   friend class WebViewImpl;
 };
 
 DEFINE_TYPE_CASTS(WebFrameWidgetBase, WebFrameWidget, widget, true, true);
 
 }  // namespace blink
 
 #endif