cros: Default to natural scrolling if the internal diplay is a touchscreen.

ui/events/event_utils.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/events/event_utils.h"
 
+#include <vector>
+
 #include "ui/events/event.h"
+#include "ui/gfx/display.h"
+#include "ui/gfx/screen.h"
 
 namespace ui {
 
 namespace {
 int g_custom_event_types = ET_LAST;
 }  // namespace
 
 bool EventCanceledDefaultHandling(const Event& event) {
   return event.phase() == EP_POSTTARGET && event.result() != ER_UNHANDLED;
 }
 
 int RegisterCustomEventType() {
   return ++g_custom_event_types;
 }
 
 base::TimeDelta EventTimeForNow() {
   return base::TimeDelta::FromInternalValue(
       base::TimeTicks::Now().ToInternalValue());
 }
 
+bool ShouldDefaultToNaturalScroll() {
+  gfx::Screen* screen = gfx::Screen::GetScreenByType(gfx::SCREEN_TYPE_NATIVE);
+  if (!screen)
+    return false;
+  const std::vector<gfx::Display>& displays = screen->GetAllDisplays();
+  for (std::vector<gfx::Display>::const_iterator it = displays.begin();
+       it != displays.end(); ++it) {
+    const gfx::Display& display = *it;
+    if (display.IsInternal() &&
+        display.touch_support() == gfx::Display::TOUCH_SUPPORT_AVAILABLE)
+      return true;
+  }
+  return false;
+}
+
 }  // namespace ui