Enable hidpi on Linux, refactor a bit on Windows to share

ui/gfx/win/direct_write.cc

 // Copyright 2014 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/direct_write.h"
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/win/registry.h"
 #include "base/win/windows_version.h"
+#include "ui/gfx/dpi.h"
 #include "ui/gfx/switches.h"
-#include "ui/gfx/win/dpi.h"
 
 namespace gfx {
 namespace win {
 
 bool ShouldUseDirectWrite() {
   // If the flag is currently on, and we're on Win7 or above, we enable
   // DirectWrite. Skia does not require the additions to DirectWrite in QFE
   // 2670838, but a simple 'better than XP' check is not enough.
   if (base::win::GetVersion() < base::win::VERSION_WIN7)
     return false;
@@ skipping 30 matching lines @@
     return false;
 
   // Otherwise, check the field trial.
   const std::string group_name =
       base::FieldTrialList::FindFullName("DirectWrite");
   return group_name != "Disabled";
 }
 
 }  // namespace win
 }  // namespace gfx