Give the browser window's content view a CALayers

chrome/browser/ui/cocoa/browser_window_controller.mm

 // Copyright 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.h"
 
 #include <cmath>
 #include <numeric>
 
 #include "base/command_line.h"
@@ skipping 244 matching lines @@
 
 // Private(TestingAPI) init routine with testing options.
 - (id)initWithBrowser:(Browser*)browser takeOwnership:(BOOL)ownIt {
   bool hasTabStrip = browser->SupportsWindowFeature(Browser::FEATURE_TABSTRIP);
   if ((self = [super initTabWindowControllerWithTabStrip:hasTabStrip])) {
     DCHECK(browser);
     initializing_ = YES;
     browser_.reset(browser);
     ownsBrowser_ = ownIt;
     NSWindow* window = [self window];
+    // Make the content view for the window have a layer. This will make all
+    // sub-views have layers. This is necessary to ensure correct layer
+    // ordering of all child views and their layers.
+    [[window contentView] cr_setWantsLayer:YES];
     windowShim_.reset(new BrowserWindowCocoa(browser, self));
 
     // Set different minimum sizes on tabbed windows vs non-tabbed, e.g. popups.
     // This has to happen before -enforceMinWindowSize: is called further down.
     NSSize minSize = [self isTabbedWindow] ?
       NSMakeSize(400, 272) : NSMakeSize(100, 122);
     [[self window] setMinSize:minSize];
 
     // Create the bar visibility lock set; 10 is arbitrary, but should hopefully
     // be big enough to hold all locks that'll ever be needed.
@@ skipping 1983 matching lines @@
 
 - (BOOL)supportsBookmarkBar {
   return [self supportsWindowFeature:Browser::FEATURE_BOOKMARKBAR];
 }
 
 - (BOOL)isTabbedWindow {
   return browser_->is_type_tabbed();
 }
 
 @end  // @implementation BrowserWindowController(WindowType)