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..6bc382ee565035b4dd9bd7b04dd7e61f033f5f29 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)
 
@@ -60,13 +61,13 @@ bool UseTouchOptimizedUI() {
 }
 #endif  // defined(OS_WIN)
 
-const float kScaleFactorScales[] = {1.0f, 1.0f, 1.25f, 1.33f, 1.4f, 1.5f, 1.8f,
-                                    2.0f, 3.0f};
-COMPILE_ASSERT(NUM_SCALE_FACTORS == arraysize(kScaleFactorScales),
-               kScaleFactorScales_incorrect_size);
-
 }  // namespace
 
+float g_kScaleFactorScales[] = {1.0f, 1.0f, 1.25f, 1.33f, 1.4f, 1.5f, 1.8f,
+                                2.0f, 3.0f};
+COMPILE_ASSERT(NUM_SCALE_FACTORS == arraysize(g_kScaleFactorScales),
+               kScaleFactorScales_incorrect_size);
+
 DisplayLayout GetDisplayLayout() {
 #if defined(OS_WIN)
   if (UseTouchOptimizedUI())
@@ -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(g_kScaleFactorScales[*it]);
   }
   gfx::ImageSkia::SetSupportedScales(scales);
 }
@@ -106,7 +107,7 @@ ScaleFactor GetSupportedScaleFactor(float scale) {
   float smallest_diff =  std::numeric_limits<float>::max();
   for (size_t i = 0; i < g_supported_scale_factors->size(); ++i) {
     ScaleFactor scale_factor = (*g_supported_scale_factors)[i];
-    float diff = std::abs(kScaleFactorScales[scale_factor] - scale);
+    float diff = std::abs(g_kScaleFactorScales[scale_factor] - scale);
     if (diff < smallest_diff) {
       closest_match = scale_factor;
       smallest_diff = diff;
@@ -117,7 +118,11 @@ ScaleFactor GetSupportedScaleFactor(float scale) {
 }
 
 float GetImageScale(ScaleFactor scale_factor) {
-  return kScaleFactorScales[scale_factor];
+#if defined(OS_WIN)
+  if (gfx::IsHighDPIEnabled())
+    return gfx::win::GetDeviceScaleFactor();
+#endif
+  return g_kScaleFactorScales[scale_factor];
 }
 
 bool IsScaleFactorSupported(ScaleFactor scale_factor) {
@@ -135,7 +140,7 @@ ScaleFactor FindClosestScaleFactorUnsafe(float scale) {
   ScaleFactor closest_match = SCALE_FACTOR_100P;
   for (int i = SCALE_FACTOR_100P; i < NUM_SCALE_FACTORS; ++i) {
     const ScaleFactor scale_factor = static_cast<ScaleFactor>(i);
-    float diff = std::abs(kScaleFactorScales[scale_factor] - scale);
+    float diff = std::abs(g_kScaleFactorScales[scale_factor] - scale);
     if (diff < smallest_diff) {
       closest_match = scale_factor;
       smallest_diff = diff;