ozone: evdev: Don't crash without cursor in scroll & click events

ui/events/ozone/evdev/libgestures_glue/gesture_interpreter_libevdev_cros.cc

 // Copyright 2014 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/ozone/evdev/libgestures_glue/gesture_interpreter_libevdev_cros.h"
 
 #include <gestures/gestures.h>
 #include <libevdev/libevdev.h>
 
 #include "base/strings/stringprintf.h"
@@ skipping 191 matching lines @@
                    cursor_->location(),
                    cursor_->location(),
                    modifiers_->GetModifierFlags(),
                    /* changed_button_flags */ 0);
   Dispatch(&event);
 }
 
 void GestureInterpreterLibevdevCros::OnGestureScroll(
     const Gesture* gesture,
     const GestureScroll* scroll) {
+  if (!cursor_)
+    return;  // No cursor!
   DVLOG(3) << base::StringPrintf("Gesture Scroll: (%f, %f) [%f, %f]",
                                  scroll->dx,
                                  scroll->dy,
                                  scroll->ordinal_dx,
                                  scroll->ordinal_dy);
   // TODO(spang): Support SetNaturalScroll
   // TODO(spang): Use scroll->start_time
   ScrollEvent event(ET_SCROLL,
                     cursor_->location(),
                     StimeToTimedelta(gesture->end_time),
@@ skipping 26 matching lines @@
   if (buttons->up & GESTURES_BUTTON_RIGHT)
     DispatchMouseButton(EVDEV_MODIFIER_RIGHT_MOUSE_BUTTON, false);
 }
 
 void GestureInterpreterLibevdevCros::Dispatch(Event* event) {
   dispatch_callback_.Run(event);
 }
 
 void GestureInterpreterLibevdevCros::DispatchMouseButton(unsigned int modifier,
                                                          bool down) {
+  if (!cursor_)
+    return;  // No cursor!
   const gfx::PointF& loc = cursor_->location();
   int flag = modifiers_->GetEventFlagFromModifier(modifier);
   EventType type = (down ? ET_MOUSE_PRESSED : ET_MOUSE_RELEASED);
   modifiers_->UpdateModifier(modifier, down);
   MouseEvent event(type, loc, loc, modifiers_->GetModifierFlags() | flag, flag);
   Dispatch(&event);
 }
 
 }  // namespace ui