All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=880289

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=f48d91274c20fa566bb46559b2fbf0ad1a36690aa0f200ce660771c10c0e3270


Bot(s) for this bug's original alert(s):

Android Nexus5 Perf
android-nexus5x-perf

rendering.mobile - Benchmark documentation link:
  https://bit.ly/rendering-benchmarks

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/178ec713640000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/178ec713640000

Count number of active touches in TouchActionFilter by xidachen@chromium.org
https://chromium.googlesource.com/chromium/src/+/0ee2335137207b20e2dd3878adff3b1c8aac484c
236.4 → 1064 (+827.2)

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

Benchmark documentation link:
  https://bit.ly/rendering-benchmarks

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c80b63cdf21d4599153b0d9a0aec985ce0970df8

commit c80b63cdf21d4599153b0d9a0aec985ce0970df8
Author: Xida Chen <xidachen@chromium.org>
Date: Tue Sep 11 17:31:20 2018

Fix a regression by counting num of active touch sequence

Right now the TouchActionFilter::num_of_active_touches_ are incremented
in two places.
1. At InputRouterImpl::TouchEventHandled if the touch event is a touch
   sequence start.
2. At InputRouterImpl::OnTouchEventAck if it is touch sequence start and
   the ack result is NO_CONSUMER_EXISTS

The regression is due to the WebTouchEventTraits::IsTouchSequenceStart
at TouchEventHandled. Because for every touch event (touch start, touch
move, touch end), we have to go through this check.

This CL fixes this issue. Note that InputRouterImpl::TouchEventHandled
eventually calls the InputRouterImpl::OnTouchEventAck. Since the
OnTouchEventAck already checks whether the event is a touch sequence
start or not, we should put the increment in this function.

Bug: 882369,  880289 
Change-Id: I88838c31f97e17512b64387296de4c803a0228f6
Reviewed-on: https://chromium-review.googlesource.com/1216702
Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590374}
[modify] https://crrev.com/c80b63cdf21d4599153b0d9a0aec985ce0970df8/content/browser/renderer_host/input/input_router_impl.cc
[modify] https://crrev.com/c80b63cdf21d4599153b0d9a0aec985ce0970df8/content/browser/renderer_host/input/input_router_impl_unittest.cc