Fixed tab dragging which was broken on high DPI windows for scales other than 100%.

ui/gfx/screen_win.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/screen_win.h"
 
 #include <windows.h>
 
 #include "base/hash.h"
 #include "base/logging.h"
@@ skipping 47 matching lines @@
 ScreenWin::~ScreenWin() {
 }
 
 bool ScreenWin::IsDIPEnabled() {
   return IsInHighDPIMode();
 }
 
 gfx::Point ScreenWin::GetCursorScreenPoint() {
   POINT pt;
   GetCursorPos(&pt);
-  return gfx::Point(pt);
+  gfx::Point cursor_pos_pixels(pt);
+  return gfx::win::ScreenToDIPPoint(cursor_pos_pixels);
 }
 
 gfx::NativeWindow ScreenWin::GetWindowUnderCursor() {
   POINT cursor_loc;
   HWND hwnd = GetCursorPos(&cursor_loc) ? WindowFromPoint(cursor_loc) : NULL;
   return GetNativeWindowFromHWND(hwnd);
 }
 
 gfx::NativeWindow ScreenWin::GetWindowAtScreenPoint(const gfx::Point& point) {
   return GetNativeWindowFromHWND(WindowFromPoint(point.ToPOINT()));
@@ skipping 70 matching lines @@
   NOTREACHED();
   return NULL;
 }
 
 NativeWindow ScreenWin::GetNativeWindowFromHWND(HWND hwnd) const {
   NOTREACHED();
   return NULL;
 }
 
 }  // namespace gfx