Mac: Fix a recently introduced layering bug.

chrome/browser/ui/cocoa/browser_window_controller_private.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/browser_window_controller_private.h"
 
 #include <cmath>
 
 #include "base/command_line.h"
 #include "base/mac/mac_util.h"
@@ skipping 659 matching lines @@
     }
     if (showDropdown) {
       // Turn on layered mode for the window's root view for the entry
       // animation.  Without this, the OS fullscreen animation for entering
       // fullscreen mode does not correctly draw the tab strip.
       // It will be turned off (set back to NO) when the animation finishes,
       // in -windowDidEnterFullScreen:.
       // Leaving wantsLayer on for the duration of presentation mode causes
       // performance issues when the dropdown is animated in/out.  It also does
       // not seem to be required for the exit animation.
+      windowViewWantsLayer_ = [[[self window] cr_windowView] wantsLayer];
       [[[self window] cr_windowView] setWantsLayer:YES];
     }
     NSView* contentView = [[self window] contentView];
     [presentationModeController_ enterPresentationModeForContentView:contentView
                                  showDropdown:showDropdown];
   } else {
     [presentationModeController_ exitPresentationMode];
     presentationModeController_.reset();
   }
 
@@ skipping 217 matching lines @@
 
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kEnableSimplifiedFullscreen) &&
       fullscreenUrl_.is_empty()) {
     fullscreenModeController_.reset([[FullscreenModeController alloc]
         initWithBrowserWindowController:self]);
   }
 
   [self showFullscreenExitBubbleIfNecessary];
   browser_->WindowFullscreenStateChanged();
-  [[[self window] cr_windowView] setWantsLayer:NO];
+  [[[self window] cr_windowView] setWantsLayer:windowViewWantsLayer_];
   [self updateRoundedBottomCorners];
 }
 
 - (void)windowWillExitFullScreen:(NSNotification*)notification {
   if (notification)  // For System Fullscreen when non-nil.
     [self registerForContentViewResizeNotifications];
   fullscreenModeController_.reset();
   [self destroyFullscreenExitBubbleIfNecessary];
   [self setPresentationModeInternal:NO forceDropdown:NO];
 }
@@ skipping 117 matching lines @@
   }
 }
 
 - (void)updateInfoBarTipVisibility {
   // If there's no toolbar then hide the infobar tip.
   [infoBarContainerController_
       setShouldSuppressTopInfoBarTip:![self hasToolbar]];
 }
 
 @end  // @implementation BrowserWindowController(Private)