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

skia/ext/platform_canvas_mac.cc

-// Copyright (c) 2011 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/platform_canvas.h"
-
-#include "base/debug/trace_event.h"
-#include "skia/ext/bitmap_platform_device.h"
-#include "third_party/skia/include/core/SkTypes.h"
-
-namespace skia {
-
-PlatformCanvas::PlatformCanvas(int width, int height, bool is_opaque) {
-  TRACE_EVENT2("skia", "PlatformCanvas::PlatformCanvas",
-               "width", width, "height", height);
-  initialize(width, height, is_opaque);
-}
-
-PlatformCanvas::PlatformCanvas(int width,
-                               int height,
-                               bool is_opaque,
-                               CGContextRef context) {
-  TRACE_EVENT2("skia", "PlatformCanvas::PlatformCanvas",
-               "width", width, "height", height);
-  initialize(context, width, height, is_opaque);
-}
-
-PlatformCanvas::PlatformCanvas(int width,
-                               int height,
-                               bool is_opaque,
-                               uint8_t* data) {
-  TRACE_EVENT2("skia", "PlatformCanvas::PlatformCanvas",
-               "width", width, "height", height);
-  initialize(width, height, is_opaque, data);
-}
-
-PlatformCanvas::~PlatformCanvas() {
-}
-
-bool PlatformCanvas::initialize(int width,
-                                int height,
-                                bool is_opaque,
-                                uint8_t* data) {
-  return initializeWithDevice(BitmapPlatformDevice::CreateWithData(
-      data, width, height, is_opaque));
-}
-
-bool PlatformCanvas::initialize(CGContextRef context,
-                                int width,
-                                int height,
-                                bool is_opaque) {
-  return initializeWithDevice(BitmapPlatformDevice::Create(
-      context, width, height, is_opaque));
-}
-
-}  // namespace skia