Snapshot a pointer to the main frame when creating WebViewFrameWidget.

Source/web/WebViewFrameWidget.h

 // Copyright 2015 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 WebViewFrameWidget_h
 #define WebViewFrameWidget_h
 
+#include "platform/heap/Handle.h"
 #include "public/web/WebFrameWidget.h"
 #include "wtf/Noncopyable.h"
+#include "wtf/RefPtr.h"
 
 namespace blink {
 
+class WebLocalFrameImpl;
 class WebViewImpl;
+class WebWidgetClient;
 
 // Shim class to help normalize the widget interfaces in the Blink public API.
 // For OOPI, subframes have WebFrameWidgets for input and rendering.
 // Unfortunately, the main frame still uses WebView's WebWidget for input and
 // rendering. This results in complex code, since there are two different
 // implementations of WebWidget and code needs to have branches to handle both
 // cases.
 // This class allows a Blink embedder to create a WebFrameWidget that can be
 // used for the main frame. Internally, it currently wraps WebView's WebWidget
 // and just forwards almost everything to it.
 // After the embedder starts using a WebFrameWidget for the main frame,
 // WebView will be updated to no longer inherit WebWidget. The eventual goal is
 // to unfork the widget code duplicated in WebFrameWidgetImpl and WebViewImpl
 // into one class.
 // A more detailed writeup of this transition can be read at
 // https://goo.gl/7yVrnb.
 class WebViewFrameWidget : public WebFrameWidget {
     WTF_MAKE_NONCOPYABLE(WebViewFrameWidget);
 public:
-    explicit WebViewFrameWidget(WebViewImpl&);
+    explicit WebViewFrameWidget(WebWidgetClient*, WebViewImpl&, WebLocalFrameImpl&);
     virtual ~WebViewFrameWidget();
 
     // WebFrameWidget overrides:
     void close() override;
     WebSize size() override;
     void willStartLiveResize() override;
     void resize(const WebSize&) override;
     void resizePinchViewport(const WebSize&) override;
     void willEndLiveResize() override;
     void didEnterFullScreen() override;
@@ skipping 41 matching lines @@
     void didLosePointerLock() override;
     void didChangeWindowResizerRect() override;
     WebColor backgroundColor() const override;
     WebPagePopup* pagePopup() const override;
     void setTopControlsHeight(float height, bool topControlsShrinkLayoutSize) override;
     void updateTopControlsState(WebTopControlsState constraints, WebTopControlsState current, bool animate) override;
     void setVisibilityState(WebPageVisibilityState, bool isInitialState) override;
     bool forSubframe() const { return false; }
 
 private:
-    WebViewImpl* m_webView;
+    WebWidgetClient* m_client;
+    RefPtr<WebViewImpl> m_webView;
+    RefPtrWillBePersistent<WebLocalFrameImpl> m_mainFrame;
 };
 
 } // namespace blink
 
 #endif // WebViewFrameWidget_h