Revert "Round the scroll offset synced back to main instead of flooring."

Revert "Round the scroll offset synced back to main instead of flooring." and disable CompositeOpaqueFixedPosition

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

TBR=weiliangc,boliu

BUG=677686, 663291, 661754
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2629793003
Cr-Commit-Position: refs/heads/master@{#443691}
Committed: https://chromium.googlesource.com/chromium/src/+/96f33ef6f7c21303a68dc52c3e27a925fb200ce5

[flackr, 2017-01-13 13:32:56]

Description was changed from

==========
Revert "Round the scroll offset synced back to main instead of flooring."

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

BUG=677686,663291,661754
==========

to

==========
Revert "Round the scroll offset synced back to main instead of flooring."

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

BUG=677686,663291,661754
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

[flackr, 2017-01-13 13:38:45]

Description was changed from

==========
Revert "Round the scroll offset synced back to main instead of flooring."

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

BUG=677686,663291,661754
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

to

==========
Revert "Round the scroll offset synced back to main instead of flooring." and
disable CompositeOpaqueFixedPosition

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

BUG=677686,663291,661754
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

[flackr, 2017-01-13 13:38:45]

flackr@chromium.org changed reviewers:
+ schenney@chromium.org, weiliangc@chromium.org

[flackr, 2017-01-13 13:42:25]

Rounding the synced scroll position to fix a compositing bug exposed by
compositing opaque fixed position caused https://crbug.com/677686, which is
release blocking for M56, so I've prepared a revert as well as disable
compositing opaque fixed position elements by default. We'll have to target
re-enabling CompositeOpaqueFixedPosition after resolving this scroll sync issue.

[Stephen Chennney, 2017-01-13 18:37:40]

LGTM

[flackr, 2017-01-13 18:38:16]

The CQ bit was checked by flackr@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-01-13 18:38:58]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[flackr, 2017-01-13 18:39:34]

flackr@chromium.org changed reviewers:
+ boliu@chromium.org

[flackr, 2017-01-13 18:43:21]

Description was changed from

==========
Revert "Round the scroll offset synced back to main instead of flooring." and
disable CompositeOpaqueFixedPosition

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

BUG=677686,663291,661754
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

to

==========
Revert "Round the scroll offset synced back to main instead of flooring." and
disable CompositeOpaqueFixedPosition

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

TBR=weiliangc,boliu

BUG=677686,663291,661754
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

[flackr, 2017-01-13 20:47:11]

The CQ bit was unchecked by flackr@chromium.org

[flackr, 2017-01-13 20:47:12]

The CQ bit was checked by flackr@chromium.org

[commit-bot: I haz the power, 2017-01-13 20:47:45]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-13 22:05:50]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1484340432157060, "parent_rev":
"3edf9517a2f4c5468618cfae56f58d38928b2b1a", "commit_rev":
"96f33ef6f7c21303a68dc52c3e27a925fb200ce5"}

[commit-bot: I haz the power, 2017-01-13 22:06:24]

Description was changed from

==========
Revert "Round the scroll offset synced back to main instead of flooring." and
disable CompositeOpaqueFixedPosition

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

TBR=weiliangc,boliu

BUG=677686,663291,661754
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

to

==========
Revert "Round the scroll offset synced back to main instead of flooring." and
disable CompositeOpaqueFixedPosition

Reverts the commit 75a7e4cb1ec29ded2e52539259233356caa883c8
(https://codereview.chromium.org/2511473003) and additionally disables
CompositeOpaquePosition by default as that commit fixed a compositing bug
exposed by compositing more fixed position elements (https://crbug.com/663291).
Rounding the synced scroll offset introduced a regression which caused scroll
position to become unstable when zoomed in on long sites.

TBR=weiliangc,boliu

BUG=677686,663291,661754
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2629793003
Cr-Commit-Position: refs/heads/master@{#443691}
Committed:
https://chromium.googlesource.com/chromium/src/+/96f33ef6f7c21303a68dc52c3e27...
==========

[commit-bot: I haz the power, 2017-01-13 22:06:26]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/96f33ef6f7c21303a68dc52c3e27...