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

ui/base/win/hwnd_subclass.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/win/hwnd_subclass.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/singleton.h"
-#include "ui/gfx/win/dpi.h"
 #include "ui/gfx/win/hwnd_util.h"
 
 namespace {
 const char kHWNDSubclassKey[] = "__UI_BASE_WIN_HWND_SUBCLASS_PROC__";
 
 LRESULT CALLBACK WndProc(HWND hwnd,
                          UINT message,
                          WPARAM w_param,
                          LPARAM l_param) {
   ui::HWNDSubclass* wrapped_wnd_proc =
@@ skipping 138 matching lines @@
   // In most cases, |original_wnd_proc_| will take care of calling
   // DefWindowProc.
   return CallWindowProc(original_wnd_proc_, hwnd, message, w_param, l_param);
 }
 
 HWNDMessageFilter::~HWNDMessageFilter() {
   HWNDSubclass::RemoveFilterFromAllTargets(this);
 }
 
 }  // namespace ui