Always select best favicon bitmap

components/favicon/core/favicon_handler.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 COMPONENTS_FAVICON_CORE_FAVICON_HANDLER_H_
 #define COMPONENTS_FAVICON_CORE_FAVICON_HANDLER_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 50 matching lines @@
 // . Otherwise we ask the history database to update the mapping from
 //   page url to favicon url and call us back with the favicon. Remember, it is
 //   possible for the db to already have the favicon, just not the mapping
 //   between page to favicon url. The callback for this is OnFaviconData.
 //
 // OnFaviconData either updates the favicon of the current page (if the
 // db knew about the favicon), or requests the renderer to download the
 // favicon.
 //
 // When the renderer downloads favicons, it considers the entire list of
-// favicon candidates, if |download_largest_favicon_| is true, the largest
-// favicon will be used, otherwise the one that best matches the preferred size
-// is chosen (or the first one if there is no preferred  size). Once the
-// matching favicon has been determined, SetFavicon is called which updates
-// the page's favicon and notifies the database to save the favicon.
+// favicon candidates. Among those, the one that matches |target_spec_|
+// is chosen first. Once the matching favicon has been determined, SetFavicon
+// is called which updates the page's favicon and notifies the database to save
+// the favicon.
 
 class FaviconHandler {
  public:
+  class TargetSpec {
+   public:
+    static TargetSpec ForLargest();
+    static TargetSpec For16x16Dips();
+
+    TargetSpec(const TargetSpec&);
+    ~TargetSpec();
+
+    // Returns the target sizes to be fetched, sorted in ascending order.
+    // FaviconHandler will ensure a bitmap for each pixel sizes
+    // either by searching among candidates for an exact match, or by resampling
+    // the closest match.
+    std::vector<int> GetPixelSizes() const;
+
+    // Returns the maximum value instead of all.
+    int GetMaxPixelSize() const;
+
+    // Returns whether the spec is requiring the best-matching bitmap only.
+    bool WantsBestBitmapOnly() const;
+
+    // Compares two sizes in pixels, i.e. whether |size1| is a better match than
+    // |size2| for |pixel_size|.
+    bool IsBetterMatch(const gfx::Size& size1, const gfx::Size& size2) const;
+
+    // Checks if |bitmap_results| contains all bitmaps required by this
+    // specification.
+    bool HasCompleteResult(
+        const std::vector<favicon_base::FaviconRawBitmapResult>& bitmap_results)
+        const;
+
+    gfx::ImageSkia CreateImageSkia(
+        const std::vector<SkBitmap>& bitmaps,
+        const std::vector<gfx::Size>& original_bitmap_sizes) const;
+
+    gfx::Image CreateImageFromCache(
+        const std::vector<favicon_base::FaviconRawBitmapResult>& bitmap_results)
+        const;
+
+   private:
+    TargetSpec();
+
+    // Map representing the target sizes to be fetched and their corresponding
+    // scale factors.
+    std::map<int, float> pixel_sizes_;
+
+    // If true, FaviconHandler will resample candidates whenever needed to
+    // ensure that bitmaps for all |pixel_sizes| are produced.
+    bool ensure_exact_size_;
+  };
+
   class Delegate {
    public:
     // Mimics WebContents::ImageDownloadCallback.
     typedef base::Callback<void(
         int id,
         int status_code,
         const GURL& image_url,
         const std::vector<SkBitmap>& bitmaps,
         const std::vector<gfx::Size>& original_bitmap_sizes)>
         ImageDownloadCallback;
@@ skipping 66 matching lines @@
     favicon_base::IconType icon_type;
   };
 
   // Used to track a candidate for the favicon.
   struct FaviconCandidate {
     FaviconCandidate();
     ~FaviconCandidate();
 
     FaviconCandidate(const GURL& image_url,
                      const gfx::Image& image,
-                     float score,
                      favicon_base::IconType icon_type);
 
     GURL image_url;
     gfx::Image image;
-    float score;
     favicon_base::IconType icon_type;
   };
 
   // Returns the bit mask of favicon_base::IconType based on the handler's type.
   static int GetIconTypesFromHandlerType(
       FaviconDriverObserver::NotificationIconType handler_type);
 
   // Called when the history request for favicon data mapped to |url_| has
   // completed and the renderer has told us the icon URLs used by |url_|
   void OnGotInitialHistoryDataAndIconURLCandidates();
@@ skipping 20 matching lines @@
   // Triggered when a download of an image has finished.
   void OnDidDownloadFavicon(
       int id,
       int http_status_code,
       const GURL& image_url,
       const std::vector<SkBitmap>& bitmaps,
       const std::vector<gfx::Size>& original_bitmap_sizes);
 
   bool ShouldSaveFavicon();
 
-  // Updates |favicon_candidate_| and returns true if it is an exact match.
+  // Updates |favicon_candidate_| and returns true if no more candidates should
+  // be processed (e.g. an exact match was found).
   bool UpdateFaviconCandidate(const GURL& image_url,
                               const gfx::Image& image,
-                              float score,
                               favicon_base::IconType icon_type);
 
   // Sets the image data for the favicon.
   void SetFavicon(const GURL& icon_url,
                   const gfx::Image& image,
                   favicon_base::IconType icon_type);
 
   // Notifies |driver_| that FaviconHandler found an icon which matches the
   // |handler_type_| criteria. NotifyFaviconUpdated() can be called multiple
   // times for the same page if:
   // - a better match is found for |handler_type_| (e.g. newer bitmap data)
   // - Javascript changes the page's icon URLs.
   void NotifyFaviconUpdated(
       const std::vector<favicon_base::FaviconRawBitmapResult>&
           favicon_bitmap_results);
   void NotifyFaviconUpdated(const GURL& icon_url,
                             favicon_base::IconType icon_type,
                             const gfx::Image& image);
 
   // Return the current candidate if any.
   favicon::FaviconURL* current_candidate() {
     return current_candidate_index_ < image_urls_.size()
                ? &image_urls_[current_candidate_index_]
                : nullptr;
   }
 
-  // Returns the preferred size of the image. 0 means no preference (any size
-  // will do).
-  int preferred_icon_size() const {
-    return download_largest_icon_ ? 0 : gfx::kFaviconSize;
-  }
-
   // Used for FaviconService requests.
   base::CancelableTaskTracker cancelable_task_tracker_;
 
   FaviconDriverObserver::NotificationIconType handler_type_;
 
   // URL of the page we're requesting the favicon for.
   GURL url_;
 
   // Whether we got data back for the initial request to the FaviconService.
   bool got_favicon_from_history_;
@@ skipping 10 matching lines @@
   // |image_urls_| one by one.
   bool redownload_icons_;
 
   // Requests to the renderer to download favicons.
   typedef std::map<int, DownloadRequest> DownloadRequests;
   DownloadRequests download_requests_;
 
   // The combination of the supported icon types.
   const int icon_types_;
 
-  // Whether the largest icon should be downloaded.
-  const bool download_largest_icon_;
+  // Desired icon size.
+  const TargetSpec target_spec_;
 
   // The prioritized favicon candidates from the page back from the renderer.
   std::vector<favicon::FaviconURL> image_urls_;
 
   // The icon URL and the icon type of the favicon in the most recent
   // FaviconDriver::OnFaviconAvailable() notification.
   GURL notification_icon_url_;
   favicon_base::IconType notification_icon_type_;
 
   // The FaviconService which implements favicon operations. May be null during
@@ skipping 14 matching lines @@
   FaviconCandidate best_favicon_candidate_;
 
   base::WeakPtrFactory<FaviconHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FaviconHandler);
 };
 
 }  // namespace favicon
 
 #endif  // COMPONENTS_FAVICON_CORE_FAVICON_HANDLER_H_