Ensure that favicons always have 1x representation regardless of whether the platform supports it

chrome/browser/favicon/favicon_util.cc

Index: chrome/browser/favicon/favicon_util.cc
diff --git a/chrome/browser/favicon/favicon_util.cc b/chrome/browser/favicon/favicon_util.cc
index 83a9fa9e728188bd6abb1ddd6aa6e71abe07e009..6189afd3f9677f788148791cc6904ab183af598d 100644
--- a/chrome/browser/favicon/favicon_util.cc
+++ b/chrome/browser/favicon/favicon_util.cc
@@ -13,6 +13,30 @@
 #include "ui/gfx/image/image_skia.h"
 
 // static
+std::vector<ui::ScaleFactor> FaviconUtil::GetFaviconScaleFactors() {
+  const float kScale1x = ui::GetScaleFactorScale(ui::SCALE_FACTOR_100P);
+  std::vector<ui::ScaleFactor> favicon_scale_factors =
+      ui::GetSupportedScaleFactors();
+
+  // The scale factors returned from ui::GetSupportedScaleFactors() are sorted.
+  // Insert the 1x scale factor such that GetFaviconScaleFactors() is sorted as
+  // well.
+  size_t insert_index = favicon_scale_factors.size();
+  for (size_t i = 0; i < favicon_scale_factors.size(); ++i) {
+    float scale = ui::GetScaleFactorScale(favicon_scale_factors[i]);
+    if (scale == kScale1x) {
+      return favicon_scale_factors;
+    } else if (scale > kScale1x) {
+      insert_index = i;
+      break;
+    }
+  }
+  favicon_scale_factors.insert(favicon_scale_factors.begin() + insert_index,
+                               ui::SCALE_FACTOR_100P);
+  return favicon_scale_factors;
+}
+
+// static
 int FaviconUtil::DownloadFavicon(content::RenderViewHost* rvh,
                                  const GURL& url,
                                  int image_size) {
@@ -43,6 +67,6 @@ gfx::Image FaviconUtil::SelectFaviconFramesFromPNGs(
     return gfx::Image();
 
   gfx::ImageSkia resized_image_skia = SelectFaviconFrames(bitmaps,
-      ui::GetSupportedScaleFactors(), favicon_size, NULL);
+      scale_factors, favicon_size, NULL);
   return gfx::Image(resized_image_skia);
 }