Cleanup history favicon code

chrome/browser/history/history.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_HISTORY_HISTORY_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 786 matching lines @@
   //    bitmap for a.ico.
   // TODO(pkotwicz): Remove once no longer required by sync.
   void MergeFavicon(const GURL& page_url,
                     const GURL& icon_url,
                     history::IconType icon_type,
                     scoped_refptr<base::RefCountedMemory> bitmap_data,
                     const gfx::Size& pixel_size);
 
   // Used by the FaviconService to set the favicons for a page on the history
   // backend.
-  // |favicon_bitmap_data| is a listing of additional favicon bitmaps to store
-  // for |page_url|.
+  // |favicon_bitmap_data| replaces all the favicon bitmaps mapped to
+  // |page_url|.
   // |expired| and |icon_type| fields in FaviconBitmapData are ignored.
-  // |icon_url_sizes| is a mapping of all the icon urls of the favicons
-  // available for |page_url| to the sizes that those favicons are available
-  // from the web.
-  // |favicon_bitmap_data| does not need to have entries for all the icon urls
-  // or sizes listed in |icon_url_sizes|. However, the icon urls and pixel
-  // sizes in |favicon_bitmap_data| must be a subset of |icon_url_sizes|. It is
-  // important that |icon_url_sizes| be complete as mappings to favicons whose
-  // icon url or pixel size is not in |icon_url_sizes| will be deleted.
-  // Use MergeFavicon() if any of the icon URLs for |page_url| or any of the
-  // favicon sizes of the icon URLs are not known.
+  // Use MergeFavicon() if |favicon_bitmap_data| is incomplete, and favicon
+  // bitmaps in the database should be preserved if possible. For instance,
+  // favicon bitmaps from sync are 1x only. MergeFavicon() is used to avoid
+  // deleting the 2x favicon bitmap if it is present in the history backend.
   // See HistoryBackend::ValidateSetFaviconsParams() for more details on the
-  // criteria for |favicon_bitmap_data| and |icon_url_sizes| to be valid.
+  // criteria for |favicon_bitmap_data| to be valid.
   void SetFavicons(
       const GURL& page_url,
       history::IconType icon_type,
-      const std::vector<history::FaviconBitmapData>& favicon_bitmap_data,
-      const history::IconURLSizesMap& icon_url_sizes);
+      const std::vector<history::FaviconBitmapData>& favicon_bitmap_data);
 
   // Used by the FaviconService to mark the favicon for the page as being out
   // of date.
   void SetFaviconsOutOfDateForPage(const GURL& page_url);
 
   // Used by the FaviconService to clone favicons from one page to another,
   // provided that other page does not already have favicons.
   void CloneFavicons(const GURL& old_page_url, const GURL& new_page_url);
 
   // Used by the FaviconService for importing many favicons for many pages at
@@ skipping 275 matching lines @@
   // TODO(mrossetti): Move in_memory_url_index out of history_service.
   // See http://crbug.com/138321
   scoped_ptr<history::InMemoryURLIndex> in_memory_url_index_;
 
   ObserverList<history::VisitDatabaseObserver> visit_database_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryService);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_H_