cocoa browser: remove non-material toolbar support

chrome/browser/ui/cocoa/toolbar/toolbar_view_cocoa.mm

 // Copyright (c) 2011 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/toolbar/toolbar_view_cocoa.h"
 
 #import "chrome/browser/ui/cocoa/view_id_util.h"
 #import "ui/base/cocoa/nsview_additions.h"
 #include "ui/base/material_design/material_design_controller.h"
 
 @implementation ToolbarView
 
 @synthesize dividerOpacity = dividerOpacity_;
 
 // Prevent mouse down events from moving the parent window around.
 - (BOOL)mouseDownCanMoveWindow {
   return NO;
 }
 
 - (void)drawRect:(NSRect)dirtyRect {
   [self drawBackground:dirtyRect];
 }
 
-// Override of |-[BackgroundGradientView strokeColor]|; make it respect opacity.
-- (NSColor*)strokeColor {
-  // Only return a transparent color if not Material Design.
-  if (!ui::MaterialDesignController::IsModeMaterial()) {
-    return [[super strokeColor] colorWithAlphaComponent:[self dividerOpacity]];
-  }
-  return [super strokeColor];
-}
-
 - (BOOL)accessibilityIsIgnored {
   return NO;
 }
 
 - (id)accessibilityAttributeValue:(NSString*)attribute {
   if ([attribute isEqual:NSAccessibilityRoleAttribute])
     return NSAccessibilityToolbarRole;
 
   return [super accessibilityAttributeValue:attribute];
 }
 
 - (ViewID)viewID {
   return VIEW_ID_TOOLBAR;
 }
 
 - (BOOL)isOpaque {
   return YES;
 }
 
 // ThemedWindowDrawing overrides.
 
 - (void)windowDidChangeActive {
   // Need to redraw the omnibox and toolbar buttons as well.
   [self cr_recursivelySetNeedsDisplay:YES];
 }
 
 @end