ui: Remove the canvas() member from PaintContext.

ui/compositor/clip_transform_recorder.cc

 // Copyright 2015 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.
 
 #include "ui/compositor/clip_transform_recorder.h"
 
 #include "ui/compositor/paint_context.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/path.h"
 #include "ui/gfx/transform.h"
 
 namespace ui {
 
 ClipTransformRecorder::ClipTransformRecorder(const PaintContext& context)
-    : canvas_(context.canvas()) {
+    : canvas_(context.canvas_) {
   canvas_->Save();
 }
 
 ClipTransformRecorder::~ClipTransformRecorder() {
   canvas_->Restore();
 }
 
 void ClipTransformRecorder::ClipRect(const gfx::Rect& clip_rect) {
   canvas_->ClipRect(clip_rect);
 }
 
 void ClipTransformRecorder::ClipPath(const gfx::Path& clip_path) {
   bool anti_alias = false;
   canvas_->ClipPath(clip_path, anti_alias);
 }
 
 void ClipTransformRecorder::ClipPathWithAntiAliasing(
     const gfx::Path& clip_path) {
   bool anti_alias = true;
   canvas_->ClipPath(clip_path, anti_alias);
 }
 
 void ClipTransformRecorder::Transform(const gfx::Transform& transform) {
   canvas_->Transform(transform);
 }
 
 }  // namespace ui