Null check secondary_pointer_down_event_

ui/events/gesture_detection/gesture_detector.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.
 
 // MSVC++ requires this to be set before any other includes to get M_PI.
 #define _USE_MATH_DEFINES
 
 #include "ui/events/gesture_detection/gesture_detector.h"
 
 #include <stddef.h>
@@ skipping 293 matching lines @@
         const float scroll_x = last_focus_x_ - focus_x;
         const float scroll_y = last_focus_y_ - focus_y;
         if (is_double_tapping_) {
           // Give the move events of the double-tap.
           DCHECK(double_tap_listener_);
           handled |= double_tap_listener_->OnDoubleTapEvent(ev);
         } else if (all_pointers_within_slop_regions_) {
           if (!IsWithinTouchSlop(ev)) {
             handled = listener_->OnScroll(
                 *current_down_event_, ev,
-                (maximum_pointer_count_ > 1 ? *secondary_pointer_down_event_
-                                            : ev),
+                (maximum_pointer_count_ > 1 && secondary_pointer_down_event_)
+                    ? *secondary_pointer_down_event_
+                    : ev,
                 scroll_x, scroll_y);
             last_focus_x_ = focus_x;
             last_focus_y_ = focus_y;
             all_pointers_within_slop_regions_ = false;
             timeout_handler_->Stop();
           }
 
           const float delta_x = focus_x - down_focus_x_;
           const float delta_y = focus_y - down_focus_y_;
           const float distance_square = delta_x * delta_x + delta_y * delta_y;
           if (distance_square > double_tap_touch_slop_square_)
             always_in_bigger_tap_region_ = false;
         } else if (std::abs(scroll_x) > kScrollEpsilon ||
                    std::abs(scroll_y) > kScrollEpsilon) {
           handled = listener_->OnScroll(
               *current_down_event_, ev,
-              (maximum_pointer_count_ > 1 ? *secondary_pointer_down_event_
-                                          : ev),
+              (maximum_pointer_count_ > 1 && secondary_pointer_down_event_)
+                  ? *secondary_pointer_down_event_
+                  : ev,
               scroll_x, scroll_y);
           last_focus_x_ = focus_x;
           last_focus_y_ = focus_y;
         }
 
         if (!two_finger_tap_allowed_for_gesture_)
           break;
 
         // Two-finger tap should be prevented if either pointer exceeds its
         // (independent) slop region.
@@ skipping 202 matching lines @@
 bool GestureDetector::IsWithinTouchSlop(const MotionEvent& ev) {
   // If there have been more than two down pointers in the touch sequence,
   // tapping is not possible. Slop region check is not needed.
   if (maximum_pointer_count_ > 2)
     return false;
 
   for (size_t i = 0; i < ev.GetPointerCount(); i++) {
     const int pointer_id = ev.GetPointerId(i);
     const MotionEvent* source_pointer_down_event = GetSourcePointerDownEvent(
         *current_down_event_,
-        maximum_pointer_count_ > 1 ? *secondary_pointer_down_event_
-                                   : *current_down_event_,
+        (maximum_pointer_count_ > 1 && secondary_pointer_down_event_)
+            ? *secondary_pointer_down_event_
+            : *current_down_event_,
         pointer_id);
     DCHECK(source_pointer_down_event);
     if (!source_pointer_down_event)
       return false;
 
     int source_index =
         source_pointer_down_event->FindPointerIndexOfId(pointer_id);
     DCHECK_GE(source_index, 0);
     if (source_index < 0)
       return false;
@@ skipping 17 matching lines @@
   for (size_t i = 0; i < secondary_pointer_down_event.GetPointerCount(); i++) {
     if (secondary_pointer_down_event.GetPointerId(i) == pointer_id)
       return &secondary_pointer_down_event;
   }
 
   NOTREACHED();
   return nullptr;
 }
 
 }  // namespace ui