The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform/gestures/+/39acdab1b516f371a5487121caada8f10237b6f2

commit 39acdab1b516f371a5487121caada8f10237b6f2
Author: Sean O'Brien <seobrien@google.com>
Date: Tue Feb 27 06:07:35 2018

Prevent flings without a matching scroll

A fling gesture should only be generated after a scroll ends.  We use
the did_generate_scroll_ flag to track if there has been a scroll since
the last fling.  However, this flag is never set to false when a fling
is generated, so it is possible to send fling events without a matching
scroll event.

This CL sets the did_generate_scroll_ flag to false after a fling is
generated.

BUG= chromium:811855 
TEST=created a test in touchtests with multiple flings without matching
scrolls.  This CL prevents the extra flings.

Change-Id: I9b8b791b71b906e9579849e93d327359df876ddc
Reviewed-on: https://chromium-review.googlesource.com/916629
Commit-Ready: Sean O'Brien <seobrien@chromium.org>
Tested-by: Sean O'Brien <seobrien@chromium.org>
Reviewed-by: Andrew de los Reyes <adlr@chromium.org>

[modify] https://crrev.com/39acdab1b516f371a5487121caada8f10237b6f2/src/multitouch_mouse_interpreter.cc
[modify] https://crrev.com/39acdab1b516f371a5487121caada8f10237b6f2/include/immediate_interpreter.h
[modify] https://crrev.com/39acdab1b516f371a5487121caada8f10237b6f2/src/immediate_interpreter.cc