Browser Plugin: Update Guest WebContents Visibility on BrowserPlugin Visiblity Change.

content/browser/browser_plugin/browser_plugin_guest.h

 // 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.
 
 // A BrowserPluginGuest represents the browser side of browser <--> renderer
 // communication. A BrowserPlugin (a WebPlugin) is on the renderer side of
 // browser <--> guest renderer communication. The 'guest' renderer is a
 // <browser> tag.
 //
 // BrowserPluginGuest lives on the UI thread of the browser process. It has a
@@ skipping 66 matching lines @@
 
   void set_guest_hang_timeout_for_testing(const base::TimeDelta& timeout) {
     guest_hang_timeout_ = timeout;
   }
 
   void set_embedder_render_process_host(
       RenderProcessHost* render_process_host) {
     embedder_render_process_host_ = render_process_host;
   }
 
+  bool visible() const { return visible_; }
+
   // NotificationObserver implementation.
   virtual void Observe(int type,
                        const NotificationSource& source,
                        const NotificationDetails& details) OVERRIDE;
 
   // WebContentsObserver implementation.
   virtual void DidStartProvisionalLoadForFrame(
       int64 frame_id,
       bool is_main_frame,
       const GURL& validated_url,
@@ skipping 37 matching lines @@
                   const gfx::Rect& initial_pos);
   void SetCursor(const WebCursor& cursor);
   // Handles input event acks so they are sent to browser plugin host (via
   // embedder) instead of default view/widget host.
   void HandleInputEventAck(RenderViewHost* render_view_host, bool handled);
 
   // The guest needs to notify the plugin in the embedder to start (or stop)
   // accepting touch events.
   void SetIsAcceptingTouchEvents(bool accept);
 
+  // The guest WebContents is visible if both its embedder is visible and
+  // the browser plugin element is visible. If either one is not then the
+  // WebContents is marked as hidden. A hidden WebContents will consume
+  // fewer GPU and CPU resources.
+  //
+  // When the every WebContents in a RenderProcessHost is hidden, it will lower
+  // the priority of the process (see RenderProcessHostImpl::WidgetHidden).
+  //
+  // It will also send a message to the guest renderer process to cleanup
+  // resources such as dropping back buffers and adjusting memory limits (if in
+  // compositing mode, see CCLayerTreeHost::setVisible).
+  //
+  // Additionally it will slow down Javascript execution and garbage collection.
+  // See RenderThreadImpl::IdleHandler (executed when hidden) and
+  // RenderThreadImpl::IdleHandlerInForegroundTab (executed when visible).
+  void SetVisibility(bool embedder_visible, bool visible);
+
   // Exposes the protected web_contents() from WebContentsObserver.
   WebContents* GetWebContents();
 
   // Kill the guest process.
   void Terminate();
 
   // Overridden in tests.
   virtual bool ViewTakeFocus(bool reverse);
   // If possible, navigate the guest to |relative_index| entries away from the
   // current navigation entry.
@@ skipping 53 matching lines @@
   size_t damage_buffer_size_;
 #endif
   gfx::Size damage_view_size_;
   float damage_buffer_scale_factor_;
   scoped_ptr<IPC::Message> pending_input_event_reply_;
   gfx::Rect guest_rect_;
   WebCursor cursor_;
   IDMap<RenderViewHost> pending_updates_;
   int pending_update_counter_;
   base::TimeDelta guest_hang_timeout_;
+  bool visible_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserPluginGuest);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BROWSER_PLUGIN_BROWSER_PLUGIN_GUEST_H_