Add Sky framework support for drawing images

sky/engine/core/loader/NewImageLoader.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/NewImageLoader.h"
+#include "sky/engine/platform/image-decoders/ImageDecoder.h"
+#include "sky/engine/platform/SharedBuffer.h"
+
+namespace blink {
+
+void NewImageLoader::Load(const KURL& src) {
+  fetcher_ = adoptPtr(new MojoFetcher(this, src));

[abarth-chromium, 2015/05/29 23:04:10]

What happens if someone calls |Load| a second time?  We seem to null out client_
after the load is complete, which means we'll crash on a null pointer...  Maybe
we shouldn't null out the client pointer or maybe we should take the URL as a
constructor parameter.

[jackson, 2015/05/29 23:35:43]

OK, I changed it to not null the client

+}
+
+void NewImageLoader::OnReceivedResponse(mojo::URLResponsePtr response) {
+  if (response->status_code != 200) {
+    client_->notifyLoadFinished(SkBitmap());
+    client_ = nullptr;
+    return;
+  }
+  buffer_ = SharedBuffer::create();
+  drainer_ =
+      adoptPtr(new mojo::common::DataPipeDrainer(this, response->body.Pass()));
+}
+
+void NewImageLoader::OnDataAvailable(const void* data, size_t num_bytes) {
+  buffer_->append(static_cast<const char*>(data), num_bytes);
+}
+
+void NewImageLoader::OnDataComplete() {
+  OwnPtr<ImageDecoder> decoder =
+      ImageDecoder::create(*buffer_.get(), ImageSource::AlphaPremultiplied,
+                           ImageSource::GammaAndColorProfileIgnored);
+  decoder->setData(buffer_.get(), true);
+  if (decoder->failed()) {
+    client_->notifyLoadFinished(SkBitmap());
+  } else {
+    ImageFrame* frame = decoder->frameBufferAtIndex(0);

[abarth-chromium, 2015/05/29 23:04:10]

Is it possible for an image to have zero frames?  Should we check the frame
count before grabbing frame 0?

[jackson, 2015/05/29 23:35:43]

Looks like maybe. I'll add a guard

+    SkBitmap bitmap = frame->getSkBitmap();
+    client_->notifyLoadFinished(bitmap);
+  }
+  client_ = nullptr;
+}
+}

[abarth-chromium, 2015/05/29 23:04:10]

}  // namespace blink

[jackson, 2015/05/29 23:35:43]

Acknowledged.