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

ui/compositor/paint_context.h

 // 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.
 
 #ifndef UI_COMPOSITOR_PAINT_CONTEXT_H_
 #define UI_COMPOSITOR_PAINT_CONTEXT_H_
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/compositor/compositor_export.h"
@@ skipping 20 matching lines @@
   // |invalidation|.
   PaintContext(gfx::Canvas* canvas, const gfx::Rect& invalidation);
 
   // Construct a PaintContext that may only re-paint the area in the
   // |invalidation|.
   PaintContext(cc::DisplayItemList* list,
                float device_scale_factor,
                const gfx::Rect& bounds,
                const gfx::Rect& invalidation);
 
-  // Construct a PaintContext that will re-paint everything (no consideration
-  // for invalidation).
-  explicit PaintContext(gfx::Canvas* canvas);
-
   // Clone a PaintContext with an additional |offset|.
   PaintContext(const PaintContext& other, const gfx::Vector2d& offset);
 
   // Clone a PaintContext that has no consideration for invalidation.
   enum CloneWithoutInvalidation {
     CLONE_WITHOUT_INVALIDATION,
   };
   PaintContext(const PaintContext& other, CloneWithoutInvalidation c);
 
   ~PaintContext();
@@ skipping 65 matching lines @@
   // recorder is active.
   mutable bool inside_paint_recorder_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(PaintContext);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_PAINT_CONTEXT_H_