Extract Favicon Download logic from FaviconTabHelper

chrome/browser/favicon/favicon_download_helper_delegate.h

+// 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.
+
+#ifndef CHROME_BROWSER_FAVICON_FAVICON_DOWNLOAD_HELPER_DELEGATE_H_
+#define CHROME_BROWSER_FAVICON_FAVICON_DOWNLOAD_HELPER_DELEGATE_H_
+
+#include <vector>
+
+class GURL;
+class SkBitmap;
+struct FaviconURL;
+
+// This class provides a delegate interface for a FaviconDownloadHelper.  It
+// allows the FaviconDownloadHelper to pass favicon data back to its caller.
+class FaviconDownloadHelperDelegate {
+ public:
+  // Called when the icon at |image_url| has been downloaded.
+  // |bitmaps| is a list of all the frames of the icon at |image_url|.
+  virtual void OnDidDownloadFavicon(
+      int id,
+      const GURL& image_url,
+      bool errored,
+      int requested_size,
+      const std::vector<SkBitmap>& bitmaps) = 0;
+
+  // Message Handler.
+  virtual void OnUpdateFaviconURL(
+      int32 page_id,
+      const std::vector<FaviconURL>& candidates) = 0;
+};
+
+#endif  // CHROME_BROWSER_FAVICON_FAVICON_DOWNLOAD_HELPER_DELEGATE_H_