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

chrome/browser/manifest/manifest_icon_selector.cc

 // 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.
 
 #include "chrome/browser/manifest/manifest_icon_selector.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 
@@ skipping 146 matching lines @@
     }
   }
 
   return result;
 }
 
 // static
 GURL ManifestIconSelector::FindBestMatchingIcon(
     const std::vector<Manifest::Icon>& unfiltered_icons,
     const int ideal_icon_size_in_dp,
+    const int minimum_icon_size_in_dp,
     const gfx::Screen* screen) {
   const float device_scale_factor =

[mlamouri (slow - plz ping), 2015/09/16 09:58:29]

Add DCHECK() for minimum/ideal

[Lalit Maganti, 2015/09/16 11:45:26]

Done.

       screen->GetPrimaryDisplay().device_scale_factor();
   const int ideal_icon_size_in_px =
       static_cast<int>(round(ideal_icon_size_in_dp * device_scale_factor));
-
-  const float minimum_scale_factor = std::max(device_scale_factor - 1, 1.0f);
   const int minimum_icon_size_in_px =
-      static_cast<int>(round(ideal_icon_size_in_dp * minimum_scale_factor));
+      static_cast<int>(round(minimum_icon_size_in_dp * device_scale_factor));
 
   std::vector<Manifest::Icon> icons =
       ManifestIconSelector::FilterIconsByType(unfiltered_icons);
 
   ManifestIconSelector selector(ideal_icon_size_in_px,
                                 minimum_icon_size_in_px);
   int index = selector.FindBestMatchingIcon(icons, device_scale_factor);
   if (index == -1)
     return GURL();
   return icons[index].src;
 }