Don't send touchcancel on touch scroll start

content/browser/renderer_host/input/touch_event_queue.cc

Index: content/browser/renderer_host/input/touch_event_queue.cc
diff --git a/content/browser/renderer_host/input/touch_event_queue.cc b/content/browser/renderer_host/input/touch_event_queue.cc
index 6344f43f52c2860d7f11b1c90bc1dbdf427a2613..719c8b9ecee629d86a796b465a7b8a05c7a93c11 100644
--- a/content/browser/renderer_host/input/touch_event_queue.cc
+++ b/content/browser/renderer_host/input/touch_event_queue.cc
@@ -421,6 +421,9 @@ void TouchEventQueue::OnGestureScrollEvent(
   if (gesture_event.event.type != blink::WebInputEvent::GestureScrollBegin)
     return;
 
+  if (touch_scrolling_mode_ == TOUCH_SCROLLING_MODE_ABSORB_TOUCHMOVE)
+    absorbing_touch_moves_ = true;
+
   if (touch_scrolling_mode_ != TOUCH_SCROLLING_MODE_TOUCHCANCEL)
     return;
 
@@ -461,8 +464,6 @@ void TouchEventQueue::OnGestureEventAck(
   // gesture event (or even part of the current sequence).  Worst case, the
   // delay in updating the absorption state should only result in minor UI
   // glitches.
-  // TODO(rbyers): Define precise timing requirements and potentially implement
-  // mitigations for races.
   absorbing_touch_moves_ = (ack_result == INPUT_EVENT_ACK_STATE_CONSUMED);
 }