Filter GestureFlingStarts with Vx=Vy=0 in RenderWidgetHostViewChildFrame

Filter GestureFlingStarts with Vx=Vy=0 in RenderWidgetHostViewChildFrame

This CL fixes both (1) the renderer crash originally fixed by
https://codereview.chromium.org/2165043002, and (2) reverts the part
of that CL which prevents ChromeOS from having zero-velocity
GestureFlingStarts, which caused a regression in two-finger swipe
navigation for touchpad. It also moves the DCHECK from the original CL
to a new location which would have prevented the renderer crashes from
being introduced in the first place.

This CL doesn't include a test, though the test proposed by
khmel@ in https://codereview.chromium.org/2168693003 presumably will
land shortly after this CL.

BUG=627227
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2173603002
Cr-Commit-Position: refs/heads/master@{#407275}
(cherry picked from commit d51673024bb1990807d86e8acfbf7759748fbae3)

Committed: https://chromium.googlesource.com/chromium/src/+/9fce52f932fd3d1521fb113d61253c0b1482653a

[wjmaclean, 2016-07-25 21:21:02]

Description was changed from

==========
Filter GestureFlingStarts with Vx=Vy=0 in RenderWidgetHostViewChildFrame

This CL fixes both (1) the renderer crash originally fixed by
https://codereview.chromium.org/2165043002, and (2) reverts the part
of that CL which prevents ChromeOS from having zero-velocity
GestureFlingStarts, which caused a regression in two-finger swipe
navigation for touchpad. It also moves the DCHECK from the original CL
to a new location which would have prevented the renderer crashes from
being introduced in the first place.

This CL doesn't include a test, though the test proposed by
khmel@ in https://codereview.chromium.org/2168693003 presumably will
land shortly after this CL.

BUG=627227
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2173603002
Cr-Commit-Position: refs/heads/master@{#407275}
(cherry picked from commit d51673024bb1990807d86e8acfbf7759748fbae3)
==========

to

==========
Filter GestureFlingStarts with Vx=Vy=0 in RenderWidgetHostViewChildFrame

This CL fixes both (1) the renderer crash originally fixed by
https://codereview.chromium.org/2165043002, and (2) reverts the part
of that CL which prevents ChromeOS from having zero-velocity
GestureFlingStarts, which caused a regression in two-finger swipe
navigation for touchpad. It also moves the DCHECK from the original CL
to a new location which would have prevented the renderer crashes from
being introduced in the first place.

This CL doesn't include a test, though the test proposed by
khmel@ in https://codereview.chromium.org/2168693003 presumably will
land shortly after this CL.

BUG=627227
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2173603002
Cr-Commit-Position: refs/heads/master@{#407275}
(cherry picked from commit d51673024bb1990807d86e8acfbf7759748fbae3)

Committed:
https://chromium.googlesource.com/chromium/src/+/9fce52f932fd3d1521fb113d6125...
==========

[wjmaclean, 2016-07-25 21:21:04]

Committed patchset #1 (id:1) manually as
9fce52f932fd3d1521fb113d61253c0b1482653a.