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

ui/base/layout.cc

 // Copyright (c) 2012 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 "ui/base/layout.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "ui/base/touch/touch_device.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/screen.h"
 
 #if defined(OS_WIN)
 #include "base/win/metro.h"
+#include "ui/gfx/win/dpi.h"
 #include <Windows.h>
 #endif  // defined(OS_WIN)
 
 namespace ui {
 
 namespace {
 
 bool ScaleFactorComparator(const ScaleFactor& lhs, const ScaleFactor& rhs){
   return GetImageScale(lhs) < GetImageScale(rhs);
 }
@@ skipping 50 matching lines @@
   g_supported_scale_factors = new std::vector<ScaleFactor>(scale_factors);
   std::sort(g_supported_scale_factors->begin(),
             g_supported_scale_factors->end(),
             ScaleFactorComparator);
 
   // Set ImageSkia's supported scales.
   std::vector<float> scales;
   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);
 }
 
 const std::vector<ScaleFactor>& GetSupportedScaleFactors() {
   DCHECK(g_supported_scale_factors != NULL);
   return *g_supported_scale_factors;
 }
 
 ScaleFactor GetSupportedScaleFactor(float scale) {
   DCHECK(g_supported_scale_factors != NULL);
   ScaleFactor closest_match = SCALE_FACTOR_100P;
   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);
     if (diff < smallest_diff) {
       closest_match = scale_factor;
       smallest_diff = diff;
     }
   }
   DCHECK_NE(closest_match, SCALE_FACTOR_NONE);
   return closest_match;
 }
 
+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) {
-  return kScaleFactorScales[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(),
                    g_supported_scale_factors->end(),
                    scale_factor) != g_supported_scale_factors->end();
 }
 
 // Returns the scale factor closest to |scale| from the full list of factors.
@@ skipping 43 matching lines @@
   gfx::Screen* screen = gfx::Screen::GetScreenFor(view);
   if (screen->IsDIPEnabled()) {
     gfx::Display display = screen->GetDisplayNearestWindow(view);
     return GetSupportedScaleFactor(display.device_scale_factor());
   }
   return ui::SCALE_FACTOR_100P;
 }
 #endif  // !defined(OS_MACOSX)
 
 }  // namespace ui