manifest: rework icon selector to include small icon cut-off

chrome/browser/manifest/manifest_icon_selector.h

 // Copyright 2015 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_MANIFEST_MANIFEST_ICON_SELECTOR_H_
 #define CHROME_BROWSER_MANIFEST_MANIFEST_ICON_SELECTOR_H_
 
 #include "base/basictypes.h"
 #include "content/public/common/manifest.h"
 #include "url/gurl.h"
@@ skipping 15 matching lines @@
 class ManifestIconSelector {
  public:
   // Runs the algorithm to find the best matching icon in the icons listed in
   // the Manifest.
   //
   // Size is defined in Android's density-independent pixels (dp):
   // http://developer.android.com/guide/practices/screens_support.html
   // If/when this class is generalized, it may be a good idea to switch this to
   // taking in pixels, instead.
   //
+  // The icon returned will have a minimum size of an image one density bucket
+  // smaller than the device denisity * preferred_icon_size_in_dp.
+  //
   // Returns the icon url if a suitable icon is found. An empty URL otherwise.
   static GURL FindBestMatchingIcon(
       const std::vector<content::Manifest::Icon>& icons,
       float preferred_icon_size_in_dp,
       const gfx::Screen* screen);
 
  private:
-  explicit ManifestIconSelector(float preferred_icon_size_in_pixels);
+  ManifestIconSelector(float preferred_icon_size_in_pixels,
+                       float minimum_icon_size_in_pixels);
   virtual ~ManifestIconSelector() {}
 
   // Runs the algorithm to find the best matching icon in the icons listed in
   // the Manifest.
   // Returns the icon url if a suitable icon is found. An empty URL otherwise.
-  GURL FindBestMatchingIcon(
+  int FindBestMatchingIcon(
       const std::vector<content::Manifest::Icon>& icons,
       float density);
 
   // Runs an algorithm only based on icon declared sizes. It will try to find
   // size that is the closest to preferred_icon_size_in_pixels_ but bigger than
   // preferred_icon_size_in_pixels_ if possible.
-  // Returns the icon url if a suitable icon is found. An empty URL otherwise.
-  GURL FindBestMatchingIconForDensity(
+  // Returns the index of a suitable icon if one is found. -1 otherwise.
+  int FindBestMatchingIconForDensity(
       const std::vector<content::Manifest::Icon>& icons,
       float density);
 
   // Returns whether the |preferred_icon_size_in_pixels_| is in |sizes|.
   bool IconSizesContainsPreferredSize(const std::vector<gfx::Size>& sizes);
 
+  // Returns whether a size bigger than |minimun_icon_size_in_pixels_| is in
+  // |sizes|.
+  bool IconSizesContainsBiggerThanMinimumSize(
+      const std::vector<gfx::Size>& sizes);
+
   // Returns an array containing the items in |icons| without the unsupported
   // image MIME types.
   static std::vector<content::Manifest::Icon> FilterIconsByType(
       const std::vector<content::Manifest::Icon>& icons);
 
   // Returns whether the 'any' (ie. gfx::Size(0,0)) is in |sizes|.
   static bool IconSizesContainsAny(const std::vector<gfx::Size>& sizes);
 
   const int preferred_icon_size_in_pixels_;
+  const int minimum_icon_size_in_pixels_;
 
   friend class ManifestIconSelectorTest;
 
   DISALLOW_COPY_AND_ASSIGN(ManifestIconSelector);
 };
 
 #endif  // CHROME_BROWSER_MANIFEST_MANIFEST_ICON_SELECTOR_H_