Always reset touch action at the beginning of a new gesture sequence

content/browser/renderer_host/input/touch_action_filter.cc

Index: content/browser/renderer_host/input/touch_action_filter.cc
diff --git a/content/browser/renderer_host/input/touch_action_filter.cc b/content/browser/renderer_host/input/touch_action_filter.cc
index 14e84229faf57abec6ef384a58fad69c162fef1e..7cb12462aff67cc5e6e0d5edd09ab63311421086 100644
--- a/content/browser/renderer_host/input/touch_action_filter.cc
+++ b/content/browser/renderer_host/input/touch_action_filter.cc
@@ -90,7 +90,6 @@ bool TouchActionFilter::FilterGestureEvent(WebGestureEvent* gesture_event) {
 }
 
 bool TouchActionFilter::FilterScrollEndingGesture() {
-  allowed_touch_action_ = TOUCH_ACTION_AUTO;
   DCHECK(!drop_pinch_gesture_events_);
   if (drop_scroll_gesture_events_) {
     drop_scroll_gesture_events_ = false;
@@ -114,6 +113,10 @@ void TouchActionFilter::OnSetTouchAction(TouchAction touch_action) {
   allowed_touch_action_ = Intersect(allowed_touch_action_, touch_action);
 }
 
+void TouchActionFilter::StartNewTouchActionSequence() {
+  allowed_touch_action_ = TOUCH_ACTION_AUTO;

[Rick Byers, 2014/02/18 22:01:15]

I think you can DCHECK that our other state is consistent with the idea that
we're starting a new gesture sequence (i.e. !drop_scroll_gesture_events and
!drop_pinch_gesture_events), right?  Delayed taps is, as we've discussed,
trickier and probably subtly broken today.

[tdresser, 2014/02/20 18:37:56]

Done. I DCHECK(!drop_current_tap_ending_event) when we get a
WebInputEvent::GestureTapDown, so we at least have some coverage on that.

+}
+
 bool TouchActionFilter::ShouldSuppressScroll(
     const blink::WebGestureEvent& gesture_event) {
   DCHECK_EQ(gesture_event.type, WebInputEvent::GestureScrollBegin);