Turn on natural scrolling if we detect a touchscreen.

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.cc
===================================================================
--- chrome/browser/chromeos/chrome_browser_main_chromeos.cc	(revision 230511)
+++ chrome/browser/chromeos/chrome_browser_main_chromeos.cc	(working copy)
@@ -109,6 +109,8 @@
 #include "net/base/network_change_notifier.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context_getter.h"
+#include "ui/base/events/event_utils.h"
+#include "ui/base/touch/touch_device.h"
 
 // Exclude X11 dependents for ozone
 #if defined(USE_X11)
@@ -683,6 +685,13 @@
   // adjusting the oom priority.
   g_browser_process->platform_part()->oom_priority_manager()->Start();
 
+     // Turn on natural scroll if we have a touch screen.
+  if (ui::IsTouchDevicePresent()) {
+    CommandLine::ForCurrentProcess()->AppendSwitch(
+    chromeos::switches::kNaturalScrollDefault);
+    ui::SetNaturalScroll(true);
+ }
+
   ChromeBrowserMainPartsLinux::PreBrowserStart();
 }