Fire visibilityChange event on out-of-process iframes.

third_party/WebKit/public/web/WebViewClient.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 221 matching lines @@
     // Zoom ----------------------------------------------------------------
 
     // Informs the browser that the zoom levels for this frame have changed from
     // the default values.
     virtual void zoomLimitsChanged(double minimumLevel, double maximumLevel) { }
 
     // Informs the browser that the page scale has changed.
     virtual void pageScaleFactorChanged() { }
 
 
-    // Visibility -----------------------------------------------------------
-
-    // Returns the current visibility of the WebView.
-    virtual WebPageVisibilityState visibilityState() const
-    {
-        return WebPageVisibilityStateVisible;
-    }
-
-
     // Content detection ----------------------------------------------------
 
     // Retrieves detectable content (e.g., email addresses, phone numbers)
     // around a hit test result. The embedder should use platform-specific
     // content detectors to analyze the region around the hit test result.
     virtual WebContentDetectionResult detectContentAround(const WebHitTestResult&) { return WebContentDetectionResult(); }
 
     // Schedules a new content intent with the provided url.
     // The boolean flag is set to true when the user gesture has been applied
     // to the element from the main frame.
@@ skipping 43 matching lines @@
     WebRect windowRect() override { return WebRect(); }
     WebRect windowResizerRect() override { return WebRect(); }
 
 protected:
     ~WebViewClient() { }
 };
 
 } // namespace blink
 
 #endif