Fire visibilityChange event on out-of-process iframes.

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 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.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <stddef.h>
 
 #include <cmath>
 #include <utility>
@@ skipping 1295 matching lines @@
 
   for (RenderWidgetHostView* view : GetRenderWidgetHostViewsInTree()) {
     if (view) {
       view->Show();
 #if defined(OS_MACOSX)
       view->SetActive(true);
 #endif
     }
   }
 
+  SendPageMessage(new PageMsg_WasShown(MSG_ROUTING_NONE));
+
   last_active_time_ = base::TimeTicks::Now();
 
   // The resize rect might have changed while this was inactive -- send the new
   // one to make sure it's up to date.
   RenderViewHostImpl* rvh = GetRenderViewHost();
   if (rvh) {
     rvh->GetWidget()->ResizeRectChanged(
         GetRootWindowResizerRect(rvh->GetWidget()));
   }
 
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, WasShown());
 
   should_normally_be_visible_ = true;
 }
 
 void WebContentsImpl::WasHidden() {
   // If there are entities capturing screenshots or video (e.g., mirroring),
   // don't activate the "disable rendering" optimization.
   if (capturer_count_ == 0) {
     // |GetRenderViewHost()| can be NULL if the user middle clicks a link to
     // open a tab in the background, then closes the tab before selecting it.
     // This is because closing the tab calls WebContentsImpl::Destroy(), which
     // removes the |GetRenderViewHost()|; then when we actually destroy the
     // window, OnWindowPosChanged() notices and calls WasHidden() (which
     // calls us).
     for (RenderWidgetHostView* view : GetRenderWidgetHostViewsInTree()) {
       if (view)
         view->Hide();
     }
+
+    SendPageMessage(new PageMsg_WasHidden(MSG_ROUTING_NONE));

[dcheng, 2016/05/24 20:38:23]

MSG_ROUTING_NONE? This looks weird. Either it should be a control message or we
should attach a real routing ID.

[lfg, 2016/05/24 23:33:50]

SendPageMessage() will attach the appropriate routing IDs (and we can't create
routed message classes without providing a routing ID).

   }
 
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, WasHidden());
 
   should_normally_be_visible_ = false;
 }
 
 void WebContentsImpl::WasOccluded() {
   if (capturer_count_ > 0)
     return;
@@ skipping 3684 matching lines @@
   for (RenderViewHost* render_view_host : render_view_host_set)
     render_view_host->OnWebkitPreferencesChanged();
 }
 
 void WebContentsImpl::SetJavaScriptDialogManagerForTesting(
     JavaScriptDialogManager* dialog_manager) {
   dialog_manager_ = dialog_manager;
 }
 
 }  // namespace content