Fix a regression in checking the status of the touch events.

ui/events/devices/x11/touch_factory_x11.cc

Index: ui/events/devices/x11/touch_factory_x11.cc
diff --git a/ui/events/devices/x11/touch_factory_x11.cc b/ui/events/devices/x11/touch_factory_x11.cc
index d0cc99162699f86e05c10d57570ff8eb0b230268..7044851f925009fefee23ae8e83dfc30e84d412f 100644
--- a/ui/events/devices/x11/touch_factory_x11.cc
+++ b/ui/events/devices/x11/touch_factory_x11.cc
@@ -27,11 +27,30 @@
 
 namespace ui {
 
+namespace {
+
+bool IsTouchEventsFlagDisabled() {
+  auto command_line = base::CommandLine::ForCurrentProcess();
+  bool touch_flag_status = command_line->HasSwitch(switches::kTouchEvents) &&
+      command_line->GetSwitchValueASCII(switches::kTouchEvents) ==
+          switches::kTouchEventsDisabled;
+#if defined(OS_CHROMEOS)
+  return !GetTouchEventsCrOsMasterSwitch() && touch_flag_status;

[dtapuska, 2015/11/18 20:13:05]

So the problem I have with this is that this is a singleton class and what
happens when GetTouchEventsCrOsMasterSwitch() changes underneath?

Specifically startup sequence of this class, or if the user toggles the value;
or when are settings restored. Is it ensured that they are restored before
anyone calls this singleton GetInstance call?

[afakhry, 2015/11/18 20:36:16]

Thank you for catching that! The touch events master switch for ChromeOS X11 can
change after this singleton is initialized using a debug accelerator.

I modified the code to account for that.

+#else
+  return touch_flag_status;
+#endif  // defined(OS_CHROMEOS)
+
+}
+
+}  // namespace
+
+
 TouchFactory::TouchFactory()
     : pointer_device_lookup_(),
       touch_device_list_(),
       virtual_core_keyboard_device_(-1),
-      id_generator_(0) {
+      id_generator_(0),
+      touch_events_disabled_(IsTouchEventsFlagDisabled()) {
   if (!DeviceDataManagerX11::GetInstance()->IsXInput2Available())
     return;
 
@@ -159,7 +178,7 @@ bool TouchFactory::ShouldProcessXI2Event(XEvent* xev) {
     bool is_from_master_or_float = touch_device_list_[xiev->deviceid];
     bool is_from_slave_device = !is_from_master_or_float
         && xiev->sourceid == xiev->deviceid;
-    return ui::AreTouchEventsEnabled() &&
+    return !touch_events_disabled_ &&
            IsTouchDevice(xiev->deviceid) &&
            !is_from_slave_device;
   }
@@ -179,7 +198,7 @@ bool TouchFactory::ShouldProcessXI2Event(XEvent* xev) {
   if (!pointer_device_lookup_[xiev->deviceid])
     return false;
 
-  return IsTouchDevice(xiev->deviceid) ? ui::AreTouchEventsEnabled() : true;
+  return IsTouchDevice(xiev->deviceid) ? !touch_events_disabled_ : true;
 }
 
 void TouchFactory::SetupXI2ForXWindow(Window window) {
@@ -266,7 +285,7 @@ void TouchFactory::ReleaseSlotForTrackingID(uint32 tracking_id) {
 }
 
 bool TouchFactory::IsTouchDevicePresent() {
-  return ui::AreTouchEventsEnabled() && touch_device_lookup_.any();
+  return !touch_events_disabled_ && touch_device_lookup_.any();
 }
 
 void TouchFactory::ResetForTest() {
@@ -275,6 +294,7 @@ void TouchFactory::ResetForTest() {
   touch_device_list_.clear();
   touchscreen_ids_.clear();
   id_generator_.ResetForTest();
+  touch_events_disabled_ = false;
 }
 
 void TouchFactory::SetTouchDeviceForTest(
@@ -287,6 +307,7 @@ void TouchFactory::SetTouchDeviceForTest(
     touch_device_lookup_[*iter] = true;
     touch_device_list_[*iter] = true;
   }
+  touch_events_disabled_ = false;
 }
 
 void TouchFactory::SetPointerDeviceForTest(