webapps: allow callers of icon downloader/selector to specify a minimum size

chrome/browser/manifest/manifest_icon_downloader.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_DOWNLOADER_H_
 #define CHROME_BROWSER_MANIFEST_MANIFEST_ICON_DOWNLOADER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 namespace content {
 class WebContents;
 }  // namespace content
 
 namespace gfx {
 class Size;
 }  // namespace gfx
 
 class GURL;
 
 // Helper class which downloads the icon located at a specified. If the icon
 // file contains multiple icons then it attempts to pick the one closest in size
 // bigger than or equal to ideal_icon_size_in_dp, taking into account the
 // density of the device. If a bigger icon is chosen then, the icon is scaled
-// down to be equal to ideal_icon_size_in_dp.
+// down to be equal to ideal_icon_size_in_dp. Smaller icons will be chosen down
+// to the value specified by |minimum_icon_size_in_dp|.
 class ManifestIconDownloader final {
  public:
   using IconFetchCallback = base::Callback<void(const SkBitmap&)>;
 
   ManifestIconDownloader() = delete;
   ~ManifestIconDownloader() = delete;
 
   // Returns whether the download has started.
   // It will return false if the current context or information do not allow to
   // download the image.
   static bool Download(content::WebContents* web_contents,
                        const GURL& icon_url,
                        int ideal_icon_size_in_dp,
+                       int minimum_icon_size_in_dp,
                        const IconFetchCallback& callback);
 
  private:
   // Callback run after the manifest icon downloaded successfully or the
   // download failed.
   static void OnIconFetched(int ideal_icon_size_in_px,
                             int minimum_icon_size_in_px,
                             const IconFetchCallback& callback,
                             int id,
                             int http_status_code,
                             const GURL& url,
                             const std::vector<SkBitmap>& bitmaps,
                             const std::vector<gfx::Size>& sizes);
 
   static void ScaleIcon(int ideal_icon_size_in_px,
                         const SkBitmap& bitmap,
                         const IconFetchCallback& callback);
 
   static int FindClosestBitmapIndex(int ideal_icon_size_in_px,
                                     int minimum_icon_size_in_px,
                                     const std::vector<SkBitmap>& bitmaps);
 
   friend class ManifestIconDownloaderTest;
 
   DISALLOW_COPY_AND_ASSIGN(ManifestIconDownloader);
 };
 
 #endif  // CHROME_BROWSER_MANIFEST_MANIFEST_ICON_DOWNLOADER_H_