tree fe840b017949fef7401c40774b479d10ec85e456
parent 5fccf7ca2d9ce01847d0d6459db73636d537dce3
author lanwei <lanwei@chromium.org> 1480402277 -0800
committer Commit bot <commit-bot@chromium.org> 1480402454 +0000

Make touch events uncancelable during fling when they are on the current active scroll layer

In the previous patch https://codereview.chromium.org/2233543002/, we missed to check if the
touch events which we will make uncancelable when there is an active fling are on the
same layer as the current active scroll layer or its descendants.

Now, we add the scroll layer check here to minimize the breaking cases and also match with other
browsers' behavior, such as Safaris and Firefox.

This code has two parts:
1. Delete the is_fling flag we used on https://codereview.chromium.org/1923973002/
to indicate if the actice fling is happening.
2. Add check to the touch start if it hits on the same layer as the current active scroll layer.

BUG=595327

Review-Url: https://codereview.chromium.org/2471523002
Cr-Commit-Position: refs/heads/master@{#434917}