Fixed all unused-variable Clang warnings on Windows.

ui/gfx/win/dpi.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/gfx/win/dpi.h"
 
 #include <windows.h>
 #include "base/win/scoped_hdc.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/geometry/point_conversions.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/geometry/size_conversions.h"
 
 namespace {
 
 int kDefaultDPIX = 96;
-int kDefaultDPIY = 96;
-
-bool force_highdpi_for_testing = false;
+// int kDefaultDPIY = 96;

[Nico, 2015/07/02 17:34:26]

?

[Matt Giuca, 2015/07/03 03:46:29]

Again, I didn't want to delete this information from the code in case it was
needed in the future. Maybe this should just be "int kDefaultDPI = 96", implying
that X and Y have the same DPI (the code below seems to be making that
assumption anyway, which is why it uses kDefaultDPIX but not kDefaultDPIY).

 
 float g_device_scale_factor = 0.0f;
 
 float GetUnforcedDeviceScaleFactor() {
   // If the global device scale factor is initialized use it. This is to ensure
   // we use the same scale factor across all callsites.
   if (g_device_scale_factor)
     return g_device_scale_factor;
   return static_cast<float>(gfx::GetDPI().width()) /
       static_cast<float>(kDefaultDPIX);
@@ skipping 72 matching lines @@
   // Always ceil sizes. Otherwise we may be leaving off part of the bounds.
   return ToCeiledSize(ScaleSize(dip_size, GetDPIScale()));
 }
 
 int GetSystemMetricsInDIP(int metric) {
   return static_cast<int>(GetSystemMetrics(metric) / GetDPIScale() + 0.5);
 }
 
 }  // namespace win
 }  // namespace gfx