Find Favicon in priority of icon_type.

chrome/browser/history/history_service.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_SERVICE_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_SERVICE_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 672 matching lines @@
   // returned in the priority of TOUCH_PRECOMPOSED_ICON, TOUCH_ICON, and
   // FAVICON.
   CancelableTaskTracker::TaskId GetFavicons(
       const std::vector<GURL>& icon_urls,
       int icon_types,
       int desired_size_in_dip,
       const std::vector<ui::ScaleFactor>& desired_scale_factors,
       const FaviconService::FaviconResultsCallback& callback,
       CancelableTaskTracker* tracker);
 
-  // Used by the FaviconService to get favicons mapped to |page_url| for
-  // |icon_types| which most closely match |desired_size_in_dip| and
-  // |desired_scale_factors|. If |desired_size_in_dip| is 0, the largest favicon
-  // bitmap for |icon_types| is returned. The returned FaviconBitmapResults will
+  // Used by the FaviconService to get favicons mapped to |params.page_url| for
+  // icon_types in |params.icon_types| which most closely match
+  // |params.desired_size_in_dip| and |desired_scale_factors|.
+  // If |desired_size_in_dip| is 0, the largest favicon bitmap for
+  // |params.icon_types| is returned. The returned FaviconBitmapResults will
   // have at most one result for each of |desired_scale_factors|. If a favicon
   // bitmap is determined to be the best candidate for multiple scale factors
-  // there will be less results. If |icon_types| has several types, results for
+  // there will be less results.
+  // |params.icon_types| is a list of icon_type composition and defines the
+  // prefered icon types in priority.
+  // If it has only one element, and this element has several types, results for
   // only a single type will be returned in the priority of
   // TOUCH_PRECOMPOSED_ICON, TOUCH_ICON, and FAVICON.
+  // if it has more than one element, there is only one icon returned by below
+  // rule:
+  // Among all icons found by |params.desired_size_in_dip| and
+  // |desired_scal_factors|, the largest icon of first types given by
+  // |params.icon_types| is returned, if its size is larger than
+  // |params.threshold_for_next_icon_types|; otherwise, find the largest one
+  // in next icon types in |params.icon_types| and so on.
+  // If none icon is larger than |threshold_for_next_icon_types|, the largest
+  // one among all found icon is returned.
+  // This feature is especially useful when some types of icon is perfered as
+  // long as its size is larger than a specific value.
   CancelableTaskTracker::TaskId GetFaviconsForURL(
-      const GURL& page_url,
-      int icon_types,
-      int desired_size_in_dip,
+      const FaviconService::FaviconForURLParams& params,
       const std::vector<ui::ScaleFactor>& desired_scale_factors,
       const FaviconService::FaviconResultsCallback& callback,
       CancelableTaskTracker* tracker);
 
   // Used by the FaviconService to get the favicon bitmap which most closely
   // matches |desired_size_in_dip| and |desired_scale_factor| from the favicon
   // with |favicon_id| from the history backend. If |desired_size_in_dip| is 0,
   // the largest favicon bitmap for |favicon_id| is returned.
   CancelableTaskTracker::TaskId GetFaviconForID(
       chrome::FaviconID favicon_id,
@@ skipping 347 matching lines @@
   scoped_ptr<history::InMemoryURLIndex> in_memory_url_index_;
 
   ObserverList<history::VisitDatabaseObserver> visit_database_observers_;
 
   history::DeleteDirectiveHandler delete_directive_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryService);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_SERVICE_H_