Fire visibilityChange event on out-of-process iframes.

content/public/renderer/render_frame.h

 // Copyright 2013 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 CONTENT_PUBLIC_RENDERER_RENDER_FRAME_H_
 #define CONTENT_PUBLIC_RENDERER_RENDER_FRAME_H_
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "base/callback_forward.h"
 #include "base/strings/string16.h"
 #include "content/common/content_export.h"
 #include "content/public/common/console_message_level.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
+#include "third_party/WebKit/public/platform/WebPageVisibilityState.h"
 #include "third_party/WebKit/public/web/WebNavigationPolicy.h"
 
 class GURL;
 
 namespace blink {
 class WebFrame;
 class WebLocalFrame;
 class WebPlugin;
 class WebURLRequest;
 class WebURLResponse;
@@ skipping 166 matching lines @@
   // Adds |message| to the DevTools console.
   virtual void AddMessageToConsole(ConsoleMessageLevel level,
                                    const std::string& message) = 0;
 
   // Whether or not this frame is using Lo-Fi.
   virtual bool IsUsingLoFi() const = 0;
 
   // Whether or not this frame is currently pasting.
   virtual bool IsPasting() const = 0;
 
+  // Returns the current visibility of the frame.
+  virtual blink::WebPageVisibilityState GetVisibilityState() const = 0;
+
  protected:
   ~RenderFrame() override {}
 
  private:
   // This interface should only be implemented inside content.
   friend class RenderFrameImpl;
   RenderFrame() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_RENDERER_RENDER_FRAME_H_