Mac: Use Mavericks occlusion APIs for power savings.

content/browser/renderer_host/render_widget_host_view_mac.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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <IOSurface/IOSurfaceAPI.h>
 #include <list>
@@ skipping 359 matching lines @@
   // someone (other than superview) has retained |cocoa_view_|.
   RenderWidgetHostImpl* render_widget_host_;
 
   // Current text input type.
   ui::TextInputType text_input_type_;
   bool can_compose_inline_;
 
   // The background CoreAnimation layer which is hosted by |cocoa_view_|.
   base::scoped_nsobject<CALayer> background_layer_;
 
+  // The state of |delegated_frame_host_| and |browser_compositor_view_| to
+  // manage being visible, hidden, or occluded.
+  enum BrowserCompositorViewState {
+    // Effects:
+    // - |browser_compositor_view_| exists and |delegated_frame_host_| is
+    //    visible.
+    // Happens when:
+    // - |render_widet_host_| is in the visible state (this includes when
+    //   the tab isn't visible, but tab capture is enabled).
+    BrowserCompositorActive,
+    // Effects:
+    // - |browser_compositor_view_| exists, but |delegated_frame_host_| has
+    //   been hidden.
+    // Happens when:
+    // - The |render_widget_host_| is hidden, but |cocoa_view_| is still in the
+    //   NSWindow hierarchy.
+    // - This happens when |cocoa_view_| is occluded by another window. The

[Andre, 2014/10/30 03:19:26]

Occlusion also happens when the window is minimized, and when the app is hidden.

[ccameron, 2014/10/30 19:23:33]

Done.

+    //   |browser_compositor_view_| and its CALayers are kept around so that we
+    //   will have content to show when we are un-occluded.
+    BrowserCompositorSuspended,
+    // Effects:
+    // - |browser_compositor_view_| has been destroyed and
+    //   |delegated_frame_host_| has been hidden. This is for situations where

[miu, 2014/10/30 18:33:44]

s/This is for situations where//

[ccameron, 2014/10/30 19:23:33]

Done.

+    // Happens when:
+    // - The |render_widget_host_| is hidden or dead, and |cocoa_view_| is not
+    //   attached to a NSWindow.
+    // - This happens for backgrounded tabs.
+    BrowserCompositorDestroyed,
+  };

[Avi (use Gerrit), 2014/10/30 19:32:52]

I love these comments.

+  BrowserCompositorViewState browser_compositor_state_;
+
   // Delegated frame management and compositior.
   scoped_ptr<DelegatedFrameHost> delegated_frame_host_;
   scoped_ptr<ui::Layer> root_layer_;
 
-  // Container for the NSView drawn by the browser compositor.
+  // Container for the CALayer tree drawn by the browser compositor.
   scoped_ptr<BrowserCompositorViewMac> browser_compositor_view_;
 
   // Placeholder that is allocated while browser_compositor_view_ is NULL,
   // indicating that a BrowserCompositorViewMac may be allocated. This is to
   // help in recycling the internals of BrowserCompositorViewMac.
   scoped_ptr<BrowserCompositorViewPlaceholderMac>
       browser_compositor_view_placeholder_;
 
   NSWindow* pepper_fullscreen_window() const {
     return pepper_fullscreen_window_;
@@ skipping 27 matching lines @@
   gfx::Size DesiredFrameSize() override;
   float CurrentDeviceScaleFactor() override;
   gfx::Size ConvertViewSizeToPixel(const gfx::Size& size) override;
   DelegatedFrameHost* GetDelegatedFrameHost() const override;
 
   // BrowserCompositorViewMacClient implementation.
   bool BrowserCompositorViewShouldAckImmediately() const override;
   void BrowserCompositorViewFrameSwapped(
       const std::vector<ui::LatencyInfo>& latency_info) override;
 
+  // Transition from being in the Suspended state to being in the Destroyed
+  // state, if appropriate (see BrowserCompositorViewState for details).
+  void DestroySuspendedBrowserCompositorViewIfNeeded();
+
  private:
   friend class RenderWidgetHostViewMacTest;
 
   // Returns whether this render view is a popup (autocomplete window).
   bool IsPopup() const;
 
   // Shuts down the render_widget_host_.  This is a separate function so we can
   // invoke it from the message loop.
   void ShutdownHost();
 
   // Tear down all components of the browser compositor in an order that will
   // ensure no dangling references.
   void ShutdownBrowserCompositor();
 
+  // The state of the the browser compositor and delegated frame host. See
+  // BrowserCompositorViewState for details.
   void EnsureBrowserCompositorView();
+  void SuspendBrowserCompositorView();
   void DestroyBrowserCompositorView();
 
   // IPC message handlers.
   void OnPluginFocusChanged(bool focused, int plugin_id);
   void OnStartPluginIme();
   void OnGetRenderedTextCompleted(const std::string& text);
 
   // Send updated vsync parameters to the renderer.
   void SendVSyncParametersToRenderer();
 
@@ skipping 50 matching lines @@
 
   // The current caret bounds.
   gfx::Rect caret_rect_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_