Simplify platform_canvas.h by recognizing that PlatformCanvas does not actually extend

skia/ext/bitmap_platform_device_win.cc

 // 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.
 
 #include <windows.h>
 #include <psapi.h>
 
 #include "skia/ext/bitmap_platform_device_win.h"
 #include "skia/ext/bitmap_platform_device_data.h"
 #include "skia/ext/platform_canvas.h"
@@ skipping 242 matching lines @@
 
 const SkBitmap& BitmapPlatformDevice::onAccessBitmap(SkBitmap* bitmap) {
   // FIXME(brettw) OPTIMIZATION: We should only flush if we know a GDI
   // operation has occurred on our DC.
   if (data_->IsBitmapDCCreated())
     GdiFlush();
   return *bitmap;
 }
 
 SkDevice* BitmapPlatformDevice::onCreateCompatibleDevice(
-    SkBitmap::Config config, int width, int height, bool isOpaque,
-    Usage /*usage*/) {
+    SkBitmap::Config config, int width, int height, bool isOpaque, Usage) {
   SkASSERT(config == SkBitmap::kARGB_8888_Config);
-  SkDevice* bitmap_device = BitmapPlatformDevice::CreateAndClear(width, height,
-                                                                 isOpaque);
-  return bitmap_device;
+  return BitmapPlatformDevice::CreateAndClear(width, height, isOpaque);
+}
+
+// PlatformCanvas impl
+
+SkCanvas* CreatePlatformCanvas(int width,
+                               int height,
+                               bool is_opaque,
+                               HANDLE shared_section,
+                               OnFailureType failureType) {
+  SkDevice* dev = BitmapPlatformDevice::Create(width,
+                                               height,
+                                               is_opaque,
+                                               shared_section);
+  return CreateCanvas(dev, failureType);
 }
 
 // Port of PlatformBitmap to win
 
 PlatformBitmap::~PlatformBitmap() {
   if (surface_)
     DeleteDC(surface_);
 
   HBITMAP hbitmap = (HBITMAP)platform_extra_;
   if (hbitmap)
@@ skipping 11 matching lines @@
   // When the memory DC is created, its display surface is exactly one
   // monochrome pixel wide and one monochrome pixel high. Since we select our
   // own bitmap, we must delete the previous one.
   DeleteObject(old_bitmap);
   // remember the hbitmap, so we can free it in our destructor
   platform_extra_ = (intptr_t)hbitmap;
   return true;
 }
 
 }  // namespace skia