Mac: Use Mavericks occlusion APIs for power savings.

content/browser/web_contents/web_contents_view_mac.mm

 // 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.
 
 #import <Carbon/Carbon.h>
 
 #import "content/browser/web_contents/web_contents_view_mac.h"
 
 #include <string>
 
+#include "base/mac/mac_util.h"
 #import "base/mac/scoped_sending_event.h"
 #include "base/message_loop/message_loop.h"
 #import "base/message_loop/message_pump_mac.h"
 #include "content/browser/frame_host/popup_menu_helper_mac.h"
 #include "content/browser/renderer_host/render_view_host_factory.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #import "content/browser/web_contents/web_drag_dest_mac.h"
 #import "content/browser/web_contents/web_drag_source_mac.h"
@@ skipping 566 matching lines @@
 
 // When the subviews require a layout, their size should be reset to the size
 // of this view. (It is possible for the size to get out of sync as an
 // optimization in preparation for an upcoming WebContentsView resize.
 // http://crbug.com/264207)
 - (void)resizeSubviewsWithOldSize:(NSSize)oldBoundsSize {
   for (NSView* subview in self.subviews)
     [subview setFrame:self.bounds];
 }
 
+- (void)viewWillMoveToWindow:(NSWindow*)newWindow {
+  // Occlusion notification is new in Mavericks.
+  if (base::mac::IsOSMavericksOrLater())
+    return;
+
+  NSWindow* oldWindow = [self window];
+
+  if (oldWindow) {
+    [[NSNotificationCenter defaultCenter]
+        removeObserver:self
+                  name:NSWindowDidChangeOcclusionStateNotification
+                object:oldWindow];
+  }
+
+  if (newWindow) {
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(windowChangedOcclusionState:)
+               name:NSWindowDidChangeOcclusionStateNotification
+             object:newWindow];
+  }
+}
+
+- (void)windowChangedOcclusionState:(NSNotification*)notification {
+  DCHECK(base::mac::IsOSMavericksOrLater());
+  NSWindow* window = [notification object];
+  WebContentsImpl* webContents = [self webContents];
+  if ([window occlusionState] & NSWindowOcclusionStateVisible) {
+    if (!webContents->should_normally_be_visible())
+      webContents->WasShown();
+  } else {
+    if (webContents->should_normally_be_visible())
+      webContents->WasHidden();
+  }
+}
+
 @end