Revert of force non-overlay scrollbars in all platform in flamechart

Revert of force non-overlay scrollbars in all platform in flamechart (patchset #2 id:20001 of https://codereview.chromium.org/2524783002/ )

Reason for revert:
The patch made scrollbars inconsistent on Linux. See the comment #10 in crbug.com/667455

Original issue's description:
> force non-overlay scrollbars in all platform in flamechart
> 
> Since overlay Scrollbar will make the v-scrollbar disappear in
> DevTools/Timeline. In this patch we modify the DevTools/Timeline
> v-scrollbar to custom scrollbar the same as what we did in MacOS.
> 
> BUG=667455
> 
> Review-Url: https://codereview.chromium.org/2524783002
> Cr-Commit-Position: refs/heads/master@{#471615}
> Committed: https://chromium.googlesource.com/chromium/src/+/e3bf5300114f14aedbe82f3ece0d142408ac7db7

TBR=bokan@chromium.org,caseq@chromium.org,dgozman@chromium.org,chaopeng@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667455
Review-Url: https://codereview.chromium.org/2880373003
Cr-Commit-Position: refs/heads/master@{#471862}
Committed: https://chromium.googlesource.com/chromium/src/+/463ea7fadc00a36b3a83860c64c0aa4fe0338d0a

[alph, 2017-05-15 17:49:48]

The CQ bit was checked by alph@chromium.org

[alph, 2017-05-15 17:49:49]

Created Revert of force non-overlay scrollbars in all platform in flamechart

[commit-bot: I haz the power, 2017-05-15 17:50:53]

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, 2017-05-15 19:30:01]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1494870588933120, "parent_rev":
"da737c56165f6fae6e81c488cf5821b7a77c7d1d", "commit_rev":
"463ea7fadc00a36b3a83860c64c0aa4fe0338d0a"}

[commit-bot: I haz the power, 2017-05-15 19:30:10]

Description was changed from

==========
Revert of force non-overlay scrollbars in all platform in flamechart (patchset
#2 id:20001 of https://codereview.chromium.org/2524783002/ )

Reason for revert:
The patch made scrollbars inconsistent on Linux. See the comment #10 in
crbug.com/667455

Original issue's description:
> force non-overlay scrollbars in all platform in flamechart
> 
> Since overlay Scrollbar will make the v-scrollbar disappear in
> DevTools/Timeline. In this patch we modify the DevTools/Timeline
> v-scrollbar to custom scrollbar the same as what we did in MacOS.
> 
> BUG=667455
> 
> Review-Url: https://codereview.chromium.org/2524783002
> Cr-Commit-Position: refs/heads/master@{#471615}
> Committed:
https://chromium.googlesource.com/chromium/src/+/e3bf5300114f14aedbe82f3ece0d...

TBR=bokan@chromium.org,caseq@chromium.org,dgozman@chromium.org,chaopeng@chrom...
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667455
==========

to

==========
Revert of force non-overlay scrollbars in all platform in flamechart (patchset
#2 id:20001 of https://codereview.chromium.org/2524783002/ )

Reason for revert:
The patch made scrollbars inconsistent on Linux. See the comment #10 in
crbug.com/667455

Original issue's description:
> force non-overlay scrollbars in all platform in flamechart
> 
> Since overlay Scrollbar will make the v-scrollbar disappear in
> DevTools/Timeline. In this patch we modify the DevTools/Timeline
> v-scrollbar to custom scrollbar the same as what we did in MacOS.
> 
> BUG=667455
> 
> Review-Url: https://codereview.chromium.org/2524783002
> Cr-Commit-Position: refs/heads/master@{#471615}
> Committed:
https://chromium.googlesource.com/chromium/src/+/e3bf5300114f14aedbe82f3ece0d...

TBR=bokan@chromium.org,caseq@chromium.org,dgozman@chromium.org,chaopeng@chrom...
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=667455

Review-Url: https://codereview.chromium.org/2880373003
Cr-Commit-Position: refs/heads/master@{#471862}
Committed:
https://chromium.googlesource.com/chromium/src/+/463ea7fadc00a36b3a83860c64c0...
==========

[commit-bot: I haz the power, 2017-05-15 19:30:12]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/463ea7fadc00a36b3a83860c64c0...