Ensure that extension resources are loaded with the correct scaling applied on Windows.

ui/base/layout.cc

Index: ui/base/layout.cc
diff --git a/ui/base/layout.cc b/ui/base/layout.cc
index 2c1fb51a3952706e1f6d77a0b2f29a46c2508124..10a0421f2d5f509a4b0e28cbf0e274e86cafdf01 100644
--- a/ui/base/layout.cc
+++ b/ui/base/layout.cc
@@ -20,6 +20,7 @@
 
 #if defined(OS_WIN)
 #include "base/win/metro.h"
+#include "ui/gfx/win/dpi.h"
 #include <Windows.h>
 #endif  // defined(OS_WIN)
 
@@ -90,7 +91,7 @@ void SetSupportedScaleFactors(
   for (std::vector<ScaleFactor>::const_iterator it =
           g_supported_scale_factors->begin();
        it != g_supported_scale_factors->end(); ++it) {
-    scales.push_back(GetImageScale(*it));
+    scales.push_back(GetImageScaleForScaleFactor(*it));
   }
   gfx::ImageSkia::SetSupportedScales(scales);
 }
@@ -116,10 +117,18 @@ ScaleFactor GetSupportedScaleFactor(float scale) {
   return closest_match;
 }
 
-float GetImageScale(ScaleFactor scale_factor) {
+float GetImageScaleForScaleFactor(ScaleFactor scale_factor) {
   return kScaleFactorScales[scale_factor];

[sky, 2014/03/26 20:43:27]

Is it possible to make this private too? It's confusing to have two so similar
functions.

[ananta, 2014/03/26 21:49:27]

As per our discussion, moved the kScaleFactorScales array to layout.h and
renamed it g_kScaleFactorScales. ResourceBundle uses it as well. Removed the
GetImageScaleForScaleFactor function. Verified that favicons, etc don't use the
array directly.

 }
 
+float GetImageScale(ScaleFactor scale_factor) {
+#if defined(OS_WIN)
+  if (gfx::IsHighDPIEnabled())
+    return gfx::win::GetDeviceScaleFactor();
+#endif
+  return GetImageScaleForScaleFactor(scale_factor);
+}
+
 bool IsScaleFactorSupported(ScaleFactor scale_factor) {
   DCHECK(g_supported_scale_factors != NULL);
   return std::find(g_supported_scale_factors->begin(),