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

ui/events/event_utils.cc

Index: ui/events/event_utils.cc
diff --git a/ui/events/event_utils.cc b/ui/events/event_utils.cc
index 5504e4cb39958558818b1190bf38a8a27d1c36a8..a8c95da6f8ffb475c5782c8a32cad8401731b9d2 100644
--- a/ui/events/event_utils.cc
+++ b/ui/events/event_utils.cc
@@ -4,7 +4,11 @@
 
 #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 {
 
@@ -25,4 +29,19 @@ base::TimeDelta EventTimeForNow() {
       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