Refactor the PlatformContext layer to have only one class.

base/gfx/native_theme.h

 // Copyright (c) 2006-2008 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.
 //
 // A wrapper class for working with custom XP/Vista themes provided in
 // uxtheme.dll.  This is a singleton class that can be grabbed using
 // NativeTheme::instance().
 // For more information on visual style parts and states, see:
 // http://msdn.microsoft.com/library/default.asp?url=/library/en-us/shellcc/platform/commctls/userex/topics/partsandstates.asp
 
 #ifndef BASE_GFX_NATIVE_THEME_H__
 #define BASE_GFX_NATIVE_THEME_H__
 
 #include <windows.h>
 #include <uxtheme.h>
 #include "base/basictypes.h"
 #include "base/gfx/size.h"
 #include "third_party/skia/include/core/SkColor.h"
 
 namespace skia {
-class PlatformCanvasWin;
+class PlatformCanvas;
 }  // namespace skia
 
 namespace gfx {
 
 // TODO: Define class member enums to replace part_id and state_id parameters
 // that are currently defined in <vssym32.h>. Afterward, classic_state should
 // be removed and class users wouldn't need to include <vssym32.h> anymore.
 // This would enable HOT state on non-themed UI (like when RDP'ing) and would
 // simplify usage.
 // TODO: This class should probably be changed to be platform independent at
@@ skipping 135 matching lines @@
 
   // Paints a scrollbar track section.  |align_rect| is only used in classic
   // mode, and makes sure the checkerboard pattern in |target_rect| is aligned
   // with one presumed to be in |align_rect|.
   HRESULT PaintScrollbarTrack(HDC hdc,
                               int part_id,
                               int state_id,
                               int classic_state,
                               RECT* target_rect,
                               RECT* align_rect,
-                              skia::PlatformCanvasWin* canvas) const;
+                              skia::PlatformCanvas* canvas) const;
 
   // Paints a scrollbar thumb or gripper.
   HRESULT PaintScrollbarThumb(HDC hdc,
                               int part_id,
                               int state_id,
                               int classic_state,
                               RECT* rect) const;
 
   HRESULT PaintStatusGripper(HDC hdc,
                              int part_id,
@@ skipping 10 matching lines @@
                          RECT* rect,
                          COLORREF color,
                          bool fill_content_area,
                          bool draw_edges) const;
 
   HRESULT PaintTrackbar(HDC hdc,
                         int part_id,
                         int state_id,
                         int classic_state,
                         RECT* rect,
-                        skia::PlatformCanvasWin* canvas) const;
+                        skia::PlatformCanvas* canvas) const;
 
   bool IsThemingActive() const;
 
   HRESULT GetThemePartSize(ThemeName themeName,
                            HDC hdc,
                            int part_id,
                            int state_id,
                            RECT* rect,
                            int ts,
                            SIZE* size) const;
@@ skipping 68 matching lines @@
 
   // A cache of open theme handles.
   mutable HANDLE theme_handles_[LAST];
 
   DISALLOW_EVIL_CONSTRUCTORS(NativeTheme);
 };
 
 }  // namespace gfx
 
 #endif  // BASE_GFX_NATIVE_THEME_H__