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

skia/ext/bitmap_platform_device_android.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 "skia/ext/bitmap_platform_device_android.h"
 #include "skia/ext/platform_canvas.h"
 
 namespace skia {
 
 BitmapPlatformDevice* BitmapPlatformDevice::Create(int width, int height,
@@ skipping 54 matching lines @@
   // pixels? Maybe this won't be called at all.
   return accessBitmap(true).getPixels();
 }
 
 void BitmapPlatformDevice::DrawToNativeContext(
     PlatformSurface surface, int x, int y, const PlatformRect* src_rect) {
   // Should never be called on Android.
   SkASSERT(false);
 }
 
+// PlatformCanvas impl
+
+SkCanvas* CreatePlatformCanvas(int width, int height, bool is_opaque,
+                               uint8_t* data, OnFailureType failureType) {
+  SkDevice* dev = BitmapPlatformDevice::Create(width, height, is_opaque, data);
+  return CreateCanvas(dev, failureType);
+}
+
 // Port of PlatformBitmap to android
 
 PlatformBitmap::~PlatformBitmap() {}
 
 bool PlatformBitmap::Allocate(int width, int height, bool is_opaque) {
   bitmap_.setConfig(SkBitmap::kARGB_8888_Config, width, height);
   if (!bitmap_.allocPixels())
     return false;
 
   bitmap_.setIsOpaque(is_opaque);
   surface_ = bitmap_.getPixels();
   return true;
 }
 
 }  // namespace skia