Give the browser window's content view a CALayers

chrome/browser/ui/cocoa/presentation_mode_controller.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 "chrome/browser/ui/cocoa/presentation_mode_controller.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #import "base/mac/mac_util.h"
@@ skipping 181 matching lines @@
   DCHECK(!inPresentationMode_);
   enteringPresentationMode_ = YES;
   inPresentationMode_ = YES;
   contentView_ = contentView;
   [self changeFloatingBarShownFraction:(showDropdown ? 1 : 0)];
 
   // Register for notifications.  Self is removed as an observer in |-cleanup|.
   NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
   NSWindow* window = [browserController_ window];
 
-  // When in presentation mode, the window's background will need to appear
-  // above the window contents. For this to happen, the window will need its
-  // own layer. This comes with a performance penalty when not fullscreen, so
-  // do not enable this by default.
-  [[window contentView] cr_setWantsLayer:YES];
-
   // Disable these notifications on Lion as they cause crashes.
   // TODO(rohitrao): Figure out what happens if a fullscreen window changes
   // monitors on Lion.
   if (base::mac::IsOSSnowLeopard()) {
     [nc addObserver:self
            selector:@selector(windowDidChangeScreen:)
                name:NSWindowDidChangeScreenNotification
              object:window];
 
     [nc addObserver:self
@@ skipping 15 matching lines @@
   enteringPresentationMode_ = NO;
 }
 
 - (void)exitPresentationMode {
   [[NSNotificationCenter defaultCenter]
     postNotificationName:kWillLeaveFullscreenNotification
                   object:nil];
   DCHECK(inPresentationMode_);
   inPresentationMode_ = NO;
 
-  // Remove the layer that was created.
-  NSWindow* window = [browserController_ window];
-  [[window contentView] cr_setWantsLayer:NO];
-
   [self cleanup];
 }
 
 - (void)windowDidChangeScreen:(NSNotification*)notification {
   [browserController_ resizeFullscreenWindow];
 }
 
 - (void)windowDidMove:(NSNotification*)notification {
   [browserController_ resizeFullscreenWindow];
 }
@@ skipping 401 matching lines @@
 - (void)hideActiveWindowUI {
   if (systemFullscreenMode_ != base::mac::kFullScreenModeNormal) {
     base::mac::ReleaseFullScreen(systemFullscreenMode_);
     systemFullscreenMode_ = base::mac::kFullScreenModeNormal;
   }
 
   // TODO(rohitrao): Remove the Exit Fullscreen button.  http://crbug.com/35956
 }
 
 @end