aura: A few changes to have aura_demo compile and run on linux.

ui/gfx/screen_aura.cc

 // Copyright (c) 2011 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.h"
 
+#if defined(OS_WIN)
 #include <windows.h>
+#endif
 
 #include "base/logging.h"
 
 namespace gfx {
 
 // static
 gfx::Point Screen::GetCursorScreenPoint() {
 #if defined(OS_WIN)
   POINT pt;
   GetCursorPos(&pt);
   return gfx::Point(pt);
 #endif
+  NOTIMPLEMENTED();
+  return gfx::Point();
 }
 
 // static
 gfx::Rect Screen::GetMonitorWorkAreaNearestWindow(gfx::NativeWindow window) {
   NOTIMPLEMENTED();
   return gfx::Rect();
 }
 
 // static
 gfx::Rect Screen::GetMonitorAreaNearestWindow(gfx::NativeWindow window) {
@@ skipping 16 matching lines @@
 gfx::Rect Screen::GetMonitorAreaNearestPoint(const gfx::Point& point) {
   return GetMonitorAreaOrWorkAreaNearestPoint(point, false);
 }
 
 gfx::NativeWindow Screen::GetWindowAtCursorScreenPoint() {
   NOTIMPLEMENTED();
   return NULL;
 }
 
 }  // namespace gfx