[Merge to M59] Re-add delay to PostTask in StartScrollbarPaintTimer()

[Merge to M59] Re-add delay to PostTask in StartScrollbarPaintTimer()

My previous CL removed 0.1 ms delay from PostTask in
ScrollAnimatorMac::startScrollbarPaintTimer[1] because new PostTask interface
didn't support micro sec delay (type of |delay| was changed from "double" to
"long long"). This seems to give tasks more chances to run before task
cancellation and probably contention happens.

This CL re-adds 1 ms delay (not 0.1 ms because the current PostTask doesn't
support micro sec delay as mentioned above) and confirmed it improved the scroll
animation in the demo page (see the issue).

[1] https://codereview.chromium.org/2514733002/

BUG=713669
Review-Url: https://codereview.chromium.org/2868783006
Cr-Original-Commit-Position: refs/heads/master@{#470823}
Review-Url: https://codereview.chromium.org/2907013002 .
Cr-Commit-Position: refs/branch-heads/3071@{#713}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/3b04ee85f34a041db2af572aca65a7ffc36822fe

[nhiroki, 2017-05-27 06:04:40]

Description was changed from

==========
[Merge to M59] Re-add delay to PostTask in StartScrollbarPaintTimer()

My previous CL removed 0.1 ms delay from PostTask in
ScrollAnimatorMac::startScrollbarPaintTimer[1] because new PostTask interface
didn't support micro sec delay (type of |delay| was changed from "double" to
"long long"). This seems to give tasks more chances to run before task
cancellation and probably contention happens.

This CL re-adds 1 ms delay (not 0.1 ms because the current PostTask doesn't
support micro sec delay as mentioned above) and confirmed it improved the scroll
animation in the demo page (see the issue).

[1] https://codereview.chromium.org/2514733002/

BUG=713669

Review-Url: https://codereview.chromium.org/2868783006
Cr-Commit-Position: refs/heads/master@{#470823}
(cherry picked from commit 570b67158dabf2d9f10bb12ac68762e973ed63ad)
==========

to

==========
[Merge to M59] Re-add delay to PostTask in StartScrollbarPaintTimer()

My previous CL removed 0.1 ms delay from PostTask in
ScrollAnimatorMac::startScrollbarPaintTimer[1] because new PostTask interface
didn't support micro sec delay (type of |delay| was changed from "double" to
"long long"). This seems to give tasks more chances to run before task
cancellation and probably contention happens.

This CL re-adds 1 ms delay (not 0.1 ms because the current PostTask doesn't
support micro sec delay as mentioned above) and confirmed it improved the scroll
animation in the demo page (see the issue).

[1] https://codereview.chromium.org/2514733002/

BUG=713669

Review-Url: https://codereview.chromium.org/2868783006
Cr-Original-Commit-Position: refs/heads/master@{#470823}
Review-Url: https://codereview.chromium.org/2907013002 .
Cr-Commit-Position: refs/branch-heads/3071@{#713}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/3b04ee85f34a041db2af572aca65...
==========

[nhiroki, 2017-05-27 06:04:42]

Committed patchset #1 (id:1) manually as
3b04ee85f34a041db2af572aca65a7ffc36822fe.