Add a null check for token creation to avoid crash

third_party/WebKit/Source/core/input/PointerEventManager.cpp

Index: third_party/WebKit/Source/core/input/PointerEventManager.cpp
diff --git a/third_party/WebKit/Source/core/input/PointerEventManager.cpp b/third_party/WebKit/Source/core/input/PointerEventManager.cpp
index aa42f46837b4e09bc0c4b25bce46f0f942d3b23f..0416bc2b3d8b17fa20f2346b63b38f183bb0350f 100644
--- a/third_party/WebKit/Source/core/input/PointerEventManager.cpp
+++ b/third_party/WebKit/Source/core/input/PointerEventManager.cpp
@@ -318,7 +318,8 @@ WebInputEventResult PointerEventManager::handleTouchEvents(
   // associated with so just pick the first finger.
   RefPtr<UserGestureToken> possibleGestureToken;
   if (event.type() == PlatformEvent::TouchEnd &&
-      !m_inCanceledStateForPointerTypeTouch) {
+      !m_inCanceledStateForPointerTypeTouch && !touchInfos.isEmpty() &&
+      touchInfos[0].targetFrame) {
     possibleGestureToken =
         DocumentUserGestureToken::create(touchInfos[0].targetFrame->document());
   }