Fire visibilityChange event on out-of-process iframes.

third_party/WebKit/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"
@@ skipping 70 matching lines @@
     bool isWebView() const override { return false; }
     bool isPagePopup() const override { return false; }
     void willCloseLayerTreeView() override;
     void didAcquirePointerLock() override;
     void didNotAcquirePointerLock() override;
     void didLosePointerLock() override;
     void didChangeWindowResizerRect() override;
     WebColor backgroundColor() const override;
     WebPagePopup* pagePopup() const override;
     void updateTopControlsState(WebTopControlsState constraints, WebTopControlsState current, bool animate) override;
-    void setVisibilityState(WebPageVisibilityState, bool isInitialState) override;
+    void setVisibilityState(WebPageVisibilityState) override;
     bool isTransparent() const override;
     void setIsTransparent(bool) override;
     void setBaseBackgroundColor(WebColor) override;
     bool forSubframe() const { return false; }
     void scheduleAnimation() override;
     WebWidgetClient* client() const override { return m_client; }
 
 private:
     WebWidgetClient* m_client;
     RefPtr<WebViewImpl> m_webView;
     Persistent<WebLocalFrameImpl> m_mainFrame;
 };
 
 } // namespace blink
 
 #endif // WebViewFrameWidget_h