Revert of Back PaintRecord with PaintOpBuffer instead of SkPicture

ui/views/controls/scrollbar/cocoa_scroll_bar.mm

 // Copyright 2016 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 "ui/views/controls/scrollbar/cocoa_scroll_bar.h"
 
 #import "base/mac/sdk_forward_declarations.h"
-#include "cc/paint/paint_shader.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animator.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/canvas.h"
 #include "ui/views/controls/scrollbar/base_scroll_bar_thumb.h"
 
 namespace views {
 
@@ skipping 518 matching lines @@
 CocoaScrollBarThumb* CocoaScrollBar::GetCocoaScrollBarThumb() const {
   return static_cast<CocoaScrollBarThumb*>(GetThumb());
 }
 
 // static
 base::Timer* BaseScrollBar::GetHideTimerForTest(BaseScrollBar* scroll_bar) {
   return &static_cast<CocoaScrollBar*>(scroll_bar)->hide_scrollbar_timer_;
 }
 
 }  // namespace views