Request the icon of a Web Notification in the renderer process.

content/renderer/notification_icon_loader.h

Index: content/renderer/notification_icon_loader.h
diff --git a/content/renderer/notification_icon_loader.h b/content/renderer/notification_icon_loader.h
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+// Copyright 2014 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.
+
+#ifndef CONTENT_RENDERER_NOTIFICATION_ICON_LOADER_H_
+#define CONTENT_RENDERER_NOTIFICATION_ICON_LOADER_H_
+
+#include <vector>
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "third_party/WebKit/public/platform/WebURLLoaderClient.h"
+
+class SkBitmap;
+
+namespace blink {
+class WebURL;
+struct WebURLError;
+class WebURLLoader;
+}
+
+namespace content {
+
+// Downloads the icon associated with a notification and decodes the received
+// image. This must be completed before notifications are shown to the user.
+// Icon downloaders must not be re-used for multiple notifications or icons.
+class NotificationIconLoader : public blink::WebURLLoaderClient {
+  typedef base::Callback<void(int, const SkBitmap&)> DownloadCompletedCallback;
+
+ public:
+  NotificationIconLoader(int notification_id,
+                 const DownloadCompletedCallback& callback);
+
+  virtual ~NotificationIconLoader();
+
+  // Downloads the notification's image and invokes the callback with the
+  // decoded SkBitmap when the download has succeeded, or with an empty SkBitmap
+  // in case the download has failed.
+  void Start(const blink::WebURL& icon_url);
+
+  // Cancels the current image download. The callback will not be invoked.
+  void Cancel();
+
+  // blink::WebURLLoaderClient implementation.
+  virtual void didReceiveData(blink::WebURLLoader* loader,
+                              const char* data,
+                              int data_length,
+                              int encoded_data_length);
+  virtual void didFinishLoading(blink::WebURLLoader* loader,
+                                double finish_time,
+                                int64_t total_encoded_data_length);
+  virtual void didFail(blink::WebURLLoader* loader,
+                       const blink::WebURLError& error);
+
+  int notification_id() const {
+    return notification_id_;
+  }
+
+ private:
+  int notification_id_;
+  DownloadCompletedCallback callback_;
+
+  scoped_ptr<blink::WebURLLoader> loader_;
+  bool completed_;
+
+  std::vector<uint8_t> buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(NotificationIconLoader);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_NOTIFICATION_ICON_LOADER_H_