ui: Introduce CanvasPainter, remove PaintContext(gfx::Canvas*).

ui/compositor/paint_context.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/paint_context.h"
 
 #include "third_party/skia/include/core/SkPictureRecorder.h"
 #include "ui/gfx/canvas.h"
 
 namespace ui {
@@ skipping 20 matching lines @@
       recorder_(owned_recorder_.get()),
       device_scale_factor_(device_scale_factor),
       bounds_(bounds),
       invalidation_(invalidation) {
 #if DCHECK_IS_ON()
   root_visited_ = nullptr;
   inside_paint_recorder_ = false;
 #endif
 }
 
-PaintContext::PaintContext(gfx::Canvas* canvas)
-    : PaintContext(canvas, gfx::Rect()) {
-}
-
 PaintContext::PaintContext(const PaintContext& other,
                            const gfx::Vector2d& offset)
     : canvas_(other.canvas_),
       list_(other.list_),
       owned_recorder_(nullptr),
       recorder_(other.recorder_),
       device_scale_factor_(other.device_scale_factor_),
       bounds_(other.bounds_),
       invalidation_(other.invalidation_),
       offset_(other.offset_ + offset) {
@@ skipping 16 matching lines @@
 #if DCHECK_IS_ON()
   root_visited_ = other.root_visited_;
   inside_paint_recorder_ = other.inside_paint_recorder_;
 #endif
 }
 
 PaintContext::~PaintContext() {
 }
 
 }  // namespace ui