Remove unused gfx::Canvas API

ui/gfx/canvas.h

 // Copyright (c) 2012 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_GFX_CANVAS_H_
 #define UI_GFX_CANVAS_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 371 matching lines @@
   void TileImageInt(const ImageSkia& image,
                     int src_x,
                     int src_y,
                     float tile_scale_x,
                     float tile_scale_y,
                     int dest_x,
                     int dest_y,
                     int w,
                     int h);
 
-  // Returns a native drawing context for platform specific drawing routines to
-  // use. Must be balanced by a call to EndPlatformPaint().
-  NativeDrawingContext BeginPlatformPaint();
-
-  // Signifies the end of platform drawing using the native drawing context
-  // returned by BeginPlatformPaint().
-  void EndPlatformPaint();
-
   // Apply transformation on the canvas.
   void Transform(const Transform& transform);
 
   // Draws the given string with a fade gradient at the end.
   void DrawFadedString(const base::string16& text,
                        const FontList& font_list,
                        SkColor color,
                        const Rect& display_rect,
                        int flags);
 
@@ skipping 30 matching lines @@
 
   skia::RefPtr<skia::PlatformCanvas> owned_canvas_;
   SkCanvas* canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(Canvas);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_CANVAS_H_