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

content/browser/browser_plugin/browser_plugin_guest.h

Index: content/browser/browser_plugin/browser_plugin_guest.h
diff --git a/content/browser/browser_plugin/browser_plugin_guest.h b/content/browser/browser_plugin/browser_plugin_guest.h
index 35dee2533cda515ebfed3c09df7be56a71d580b2..6d5b0e530c8d6f90814a1475fdc60a8495d82015 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.h
+++ b/content/browser/browser_plugin/browser_plugin_guest.h
@@ -81,6 +81,8 @@ class CONTENT_EXPORT BrowserPluginGuest : public WebContentsDelegate,
     embedder_render_process_host_ = render_process_host;
   }
 
+  bool visible() const { return visible_; }
+
   // WebContentsObserver implementation.
   virtual void DidStartProvisionalLoadForFrame(
       int64 frame_id,
@@ -133,6 +135,23 @@ class CONTENT_EXPORT BrowserPluginGuest : public WebContentsDelegate,
   // 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 guest WebContents is hidden, it will lower the priority of the
+  // process (see RenderProcessHostImpl::WidgetHidden).

[Charlie Reis, 2012/10/05 16:23:58]

Technically, when every WebContents in a RenderProcessHost is hidden, right?

[Fady Samuel, 2012/10/08 14:24:56]

Done.

+  //
+  // It will also send a message to the  guest renderer process to cleanup

[Charlie Reis, 2012/10/05 16:23:58]

nit: extra space

[Fady Samuel, 2012/10/08 14:24:56]

Done.

+  // 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();
 
@@ -200,6 +219,7 @@ class CONTENT_EXPORT BrowserPluginGuest : public WebContentsDelegate,
   IDMap<RenderViewHost> pending_updates_;
   int pending_update_counter_;
   base::TimeDelta guest_hang_timeout_;
+  bool visible_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserPluginGuest);
 };