Always select best favicon bitmap

components/favicon_base/select_favicon_frames.h

 // Copyright 2014 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_BASE_SELECT_FAVICON_FRAMES_H_
 #define COMPONENTS_FAVICON_BASE_SELECT_FAVICON_FRAMES_H_
 
 #include <stddef.h>
 
 #include <vector>
@@ skipping 26 matching lines @@
 // FaviconUtil::SelectFaviconFramesFromPNGs() should probably be modified too as
 // it inspired by this method.
 // If an unsupported scale (not in the favicon_base::GetFaviconScales())
 // is requested, the ImageSkia will automatically scales using lancoz3.
 gfx::ImageSkia CreateFaviconImageSkia(
     const std::vector<SkBitmap>& bitmaps,
     const std::vector<gfx::Size>& original_sizes,
     int desired_size_in_dip,
     float* score);
 
+// |desired_scale_factors| can contain 0 to represent that the corresponding
+// image shouldn't be resized. In that case, the scale factor will be computed
+// from |original_sizes|.
+gfx::ImageSkia CreateFaviconImageSkiaWithScaleFactors(
+    const std::vector<SkBitmap>& bitmaps,
+    const std::vector<gfx::Size>& original_sizes,
+    const std::vector<float>& desired_scale_factors,
+    int desired_size_in_dip);
+
 // Takes a list of the pixel sizes of a favicon's favicon bitmaps and returns
 // the indices of the best sizes to use to create an ImageSkia with
 // ImageSkiaReps with edge sizes |desired_sizes|. If '0' is one of
 // |desired_sizes|, the index of the largest size is returned. If |score| is
 // non-NULL, |score| is set to a value between 0 (bad) and 1 (good) that
 // describes how well the bitmap data with the sizes at |best_indices| will
 // produce the ImageSkia. The score is arbitrary, but it's best for exact
 // matches, and gets worse the more resampling needs to happen.
 // TODO(pkotwicz): Change API so that |desired_sizes| being empty indicates
 // that the index of the largest size is requested.
 // TODO(pkotwicz): Remove callers of this method for which |frame_pixel_sizes|
 // are the sizes of the favicon bitmaps after they were resized.
 void SelectFaviconFrameIndices(const std::vector<gfx::Size>& frame_pixel_sizes,
                                const std::vector<int>& desired_sizes,
                                std::vector<size_t>* best_indices,
                                float* score);
 
+// Returns an arbitrary, implementation specific score between [0..1] that is
+// higher for better matches, and 1.0f for exact matches. Order of preference:
+// 1) Non-huge bitmaps are preferred over huge ones (8x bigger than
+//    desired_size).
+// 2) Bitmaps which need to be scaled down instead of up.
+// 3) Bitmaps which do not need to be scaled as much.
+float GetFaviconCandidateScore(const gfx::Size& candidate_size,
+                               int desired_size);
+
 #endif  // COMPONENTS_FAVICON_BASE_SELECT_FAVICON_FRAMES_H_