[Android] Properly filter GestureFlingCancel events
The browser will drop GestureFlingCancel events when it believes the
renderer has no active fling animations. However, this filtering would
report the event as "consumed", inadverently triggering tap suppression
logic for the subsequent tap.
Instead, report "no consumer exists" for the filtered GestureFlingCancel
events, avoiding spurious tap suppression.
BUG=474882
Review URL: https://codereview.chromium.org/
1074553002
Cr-Commit-Position: refs/heads/master@{#324288}