mac: Make the avatar button layer backed.

chrome/browser/ui/cocoa/browser_window_controller_private.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 CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_CONTROLLER_PRIVATE_H_
 #define CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_CONTROLLER_PRIVATE_H_
 
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 #import "chrome/browser/ui/cocoa/presentation_mode_controller.h"
 
@@ skipping 119 matching lines @@
 - (void)enableBarVisibilityUpdates;
 - (void)disableBarVisibilityUpdates;
 
 // If there are no visibility locks and bar visibity updates are enabled, hides
 // the bar with |animation| and |delay|.  Otherwise, does nothing.
 - (void)hideOverlayIfPossibleWithAnimation:(BOOL)animation delay:(BOOL)delay;
 
 // The opacity for the toolbar divider; 0 means that it shouldn't be shown.
 - (CGFloat)toolbarDividerOpacity;
 
+// Removes the view from its superview, then adds it back in the same place.
+- (void)reAddViewToSuperview:(NSView*)view;

[Avi (use Gerrit), 2014/09/11 18:26:49]

First, this comment is not helpful; it merely restates the name of the method.

But much more importantly, name this function after _what it does_, not how it
does it. Why would someone want to call this method? What does it accomplish?
The fact that it does so by removing and re-adding the view is an implementation
detail.

I'm seriously staring at this code and it makes no sense.

[erikchen, 2014/09/12 00:32:51]

I updated the comment and the name of the method as per your suggestions.

+
 // Ensures the z-order of subviews is correct.
 - (void)updateSubviewZOrder:(BOOL)inPresentationMode;
 
 // Update visibility of the infobar tip, depending on the state of the window.
 - (void)updateInfoBarTipVisibility;
 
 // Returns the max top arrow height for infobar.
 - (NSInteger)infoBarMaxTopArrowHeight;
 
 // Configures the presentationModeController_ right after it is constructed.
@@ skipping 15 matching lines @@
     (fullscreen_mac::SlidingStyle)style;
 
 // Toggles the AppKit Fullscreen API. By default, doing so enters Canonical
 // Fullscreen.
 - (void)enterAppKitFullscreen;
 - (void)exitAppKitFullscreen;
 
 @end  // @interface BrowserWindowController(Private)
 
 #endif  // CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_CONTROLLER_PRIVATE_H_