[Material][Mac] Fix tabstrip and avatar button hierarchy

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 <utility>
 
@@ skipping 1886 matching lines @@
   return !exitingAppKitFullscreen_ &&
          (([[self window] styleMask] & NSFullScreenWindowMask) ==
               NSFullScreenWindowMask ||
           enteringAppKitFullscreen_);
 }
 
 - (CGFloat)menubarOffset {
   return [presentationModeController_ menubarOffset];
 }
 
+- (NSView*)avatarView {
+  return [avatarButtonController_ view];
+}
+
 - (void)enterWebContentFullscreen {
   // HTML5 Fullscreen should only use AppKit fullscreen in 10.10+.
   // However, if the user is using multiple monitors and turned off
   // "Separate Space in Each Display", use Immersive Fullscreen so
   // that the other monitors won't blank out.
   display::Screen* screen = display::Screen::GetScreen();
   BOOL hasMultipleMonitors = screen && screen->GetNumDisplays() > 1;
   if (base::mac::IsOSYosemiteOrLater() &&
       !(hasMultipleMonitors && ![NSScreen screensHaveSeparateSpaces])) {
     [self enterAppKitFullscreen];
@@ skipping 107 matching lines @@
 
 - (NSRect)savedRegularWindowFrame {
   return savedRegularWindowFrame_;
 }
 
 - (BOOL)isFullscreenTransitionInProgress {
   return enteringAppKitFullscreen_ || exitingAppKitFullscreen_;
 }
 
 @end  // @implementation BrowserWindowController(WindowType)