Added ImageFamily::CreateExact, which scales the best image to size.

ui/gfx/image/image_family.h

 // Copyright 2013 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 UI_GFX_IMAGE_IMAGE_FAMILY_H_
 #define UI_GFX_IMAGE_IMAGE_FAMILY_H_
 
 #include <iterator>
 #include <map>
 #include <utility>
@@ skipping 118 matching lines @@
 
   // Gets the best image to use in a rectangle of |size|.
   // Gets an image at the same aspect ratio as |size.width()|:|size.height()|,
   // if possible, or if not, the closest aspect ratio. Among images of that
   // aspect ratio, returns the smallest image with both its width and height
   // bigger or equal to the requested size. If none exists, returns the largest
   // image of that aspect ratio. If there are no images in the family, returns
   // NULL.
   const gfx::Image* GetBest(const gfx::Size& size) const;
 
+  // Gets an image of size |width|x|height|. If no image of that exact size
+  // exists, chooses the nearest larger image using GetBest() and scales it to
+  // the desired size. If there are no images in the family, returns an empty
+  // image.
+  gfx::Image CreateExact(int width, int height) const;
+
+  // Gets an image of size |size|. If no image of that exact size exists,
+  // chooses the nearest larger image using GetBest() and scales it to the
+  // desired size. If there are no images in the family, returns an empty image.
+  gfx::Image CreateExact(const gfx::Size& size) const;
+
  private:
   // Find the closest aspect ratio in the map to |desired_aspect|.
   // Ties are broken by the thinner aspect.
   // |map_| must not be empty. |desired_aspect| must be > 0.0.
   float GetClosestAspect(float desired_aspect) const;
 
   // Gets an image with aspect ratio |aspect|, at the best size for |width|.
   // Returns the smallest image of aspect ratio |aspect| with its width bigger
   // or equal to |width|. If none exists, returns the largest image of aspect
   // ratio |aspect|. Behavior is undefined if there is not at least one image in
   // |map_| of aspect ratio |aspect|.
   const gfx::Image* GetWithExactAspect(float aspect, int width) const;
 
   // Map from (aspect ratio, width) to image.
   std::map<MapKey, gfx::Image> map_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_IMAGE_IMAGE_FAMILY_H_