Move image loading out of C++ into Dart

sky/engine/core/loader/CanvasImageLoader.cpp

-// Copyright 2015 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 "sky/engine/config.h"
-#include "sky/engine/core/loader/CanvasImageLoader.h"
-#include "sky/engine/core/painting/CanvasImage.h"
-#include "sky/engine/core/script/dom_dart_state.h"
-#include "sky/engine/platform/SharedBuffer.h"
-#include "sky/engine/platform/image-decoders/ImageDecoder.h"
-
-namespace blink {
-
-CanvasImageLoader::CanvasImageLoader(const String& src, PassOwnPtr<ImageLoaderCallback> callback)
-  : callback_(callback) {
-  KURL url = KURL(DOMDartState::Current()->url(), src);
-  fetcher_ = adoptPtr(new MojoFetcher(this, url));
-}
-
-CanvasImageLoader::~CanvasImageLoader() {
-}
-
-void CanvasImageLoader::OnReceivedResponse(mojo::URLResponsePtr response) {
-  if (response->status_code != 200) {
-    callback_->handleEvent(nullptr);
-    return;
-  }
-  buffer_ = SharedBuffer::create();
-  drainer_ =
-      adoptPtr(new mojo::common::DataPipeDrainer(this, response->body.Pass()));
-}
-
-void CanvasImageLoader::OnDataAvailable(const void* data, size_t num_bytes) {
-  buffer_->append(static_cast<const char*>(data), num_bytes);
-}
-
-void CanvasImageLoader::OnDataComplete() {
-  OwnPtr<ImageDecoder> decoder =
-      ImageDecoder::create(*buffer_.get(), ImageSource::AlphaPremultiplied,
-                           ImageSource::GammaAndColorProfileIgnored);
-  decoder->setData(buffer_.get(), true);
-  if (!decoder->failed() && decoder->frameCount() > 0) {
-    RefPtr<CanvasImage> resultImage = CanvasImage::create();
-    resultImage->setBitmap(decoder->frameBufferAtIndex(0)->getSkBitmap());
-    callback_->handleEvent(resultImage.get());
-  } else {
-    callback_->handleEvent(nullptr);
-  }
-}
-
-}  // namespace blink