Make Page Visibility API work when the browser window is visible or not

ash/wm/immersive_fullscreen_controller.cc

 // 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.
 
 #include "ash/wm/immersive_fullscreen_controller.h"
 
 #include <set>
 
 #include "ash/ash_constants.h"
 #include "ash/shell.h"
@@ skipping 125 matching lines @@
 
   // Start / stop observing changes to |bubble|'s visibility.
   void StartObserving(aura::Window* bubble);
   void StopObserving(aura::Window* bubble);
 
  private:
   // Updates |revealed_lock_| based on whether any of |bubbles_| is visible.
   void UpdateRevealedLock();
 
   // aura::WindowObserver overrides:
-  void OnWindowVisibilityChanged(aura::Window* window, bool visible) override;
+  void OnWindowVisibilityChanged(aura::Window* window,
+                                 bool visible,
+                                 bool content_visible) override;
   void OnWindowDestroying(aura::Window* window) override;
 
   ImmersiveFullscreenController* controller_;
 
   std::set<aura::Window*> bubbles_;
 
   // Lock which keeps the top-of-window views revealed based on whether any of
   // |bubbles_| is visible.
   scoped_ptr<ImmersiveRevealedLock> revealed_lock_;
 
@@ skipping 59 matching lines @@
     // visibility change.
     for (std::set<aura::Window*>::const_iterator it = bubbles_.begin();
          it != bubbles_.end(); ++it) {
       AsBubbleDelegate(*it)->OnAnchorBoundsChanged();
     }
   }
 }
 
 void ImmersiveFullscreenController::BubbleManager::OnWindowVisibilityChanged(
     aura::Window*,
-    bool visible) {
+    bool visible,
+    bool content_visible) {
   UpdateRevealedLock();
 }
 
 void ImmersiveFullscreenController::BubbleManager::OnWindowDestroying(
     aura::Window* window) {
   StopObserving(window);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ skipping 710 matching lines @@
         AsBubbleDelegate(transient_child);
     if (bubble_delegate &&
         bubble_delegate->GetAnchorView() &&
         top_container_->Contains(bubble_delegate->GetAnchorView())) {
       bubble_manager_->StartObserving(transient_child);
     }
   }
 }
 
 }  // namespace ash