move favicon download code from chrome/ into content/

content/public/browser/web_contents.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 CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/process_util.h"
@@ skipping 18 matching lines @@
 class Size;
 }
 
 namespace net {
 struct LoadStateWithParam;
 }
 
 namespace content {
 
 class BrowserContext;
+class FaviconDownloadDelegate;
 class InterstitialPage;
 class RenderProcessHost;
 class RenderViewHost;
 class RenderWidgetHostView;
 class SiteInstance;
 class WebContentsDelegate;
 class WebContentsView;
 struct RendererPreferences;
 
 // Describes what goes in the main content area of a tab.
@@ skipping 337 matching lines @@
   // Returns true if the location bar should be focused by default rather than
   // the page contents. The view calls this function when the tab is focused
   // to see what it should do.
   virtual bool FocusLocationBarByDefault() = 0;
 
   // Focuses the location bar.
   virtual void SetFocusToLocationBar(bool select_all) = 0;
 
   // Does this have an opener associated with it?
   virtual bool HasOpener() const = 0;
+
+  // Starts the download of the given favicon |url| and returns the unique id of
+  // the download request. When the download is finished, an
+  // IconHostMsg_DidDownloadFavicon IPC message will be sent and passed on to
+  // the delegate via FaviconDownloadDelegate::DidDownloadFavicon().
+  // Note that |image_size| is a hint for images with multiple sizes. The
+  // downloaded image is not resized to the given image_size. If 0 is passed,
+  // the first frame of the image is returned.
+  virtual int DownloadFavicon(const GURL& url, int image_size) = 0;

[jam, 2012/11/27 01:16:31]

nit: comment is out of date (re IPC)

seems that a simpler API is to have this function takes a
FaviconDownloadDelegate as a parameter? then that way you wouldn't need
RegisterFaviconDelegate. this would also avoid the issue of a delegate being
overwritten if multiple classes fetch favicons from the same webcontents

[Cait (Slow), 2012/11/28 00:11:45]

Fixed the comment. Unfortunately, the delegate has to be set prior to the
download request being made in order to receive the new faviconURL from the
renderer (this is the purpose of the UpdateFaviconURL method on the delegate).

On 2012/11/27 01:16:31, John Abd-El-Malek wrote:

[jam, 2012/11/28 04:08:16]

can the updated url be saved in WebContents until a download is requested and
then given to the delegate then? my concern is that it will be error prone to
have a way to set a delegate which can be overwridden by other objects

+
+  virtual void RegisterFaviconDelegate(FaviconDownloadDelegate* delegate) = 0;
+
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_