Reland of DevTools: fix aggregated donut chart cache population

Reland of DevTools: fix aggregated donut chart cache population (patchset #1 id:1 of https://codereview.chromium.org/2839083002/ )

Reason for revert:
The patch has noting to do with the failing test. In fact if you look at the flakiness dashboard the test is very flaky there:

https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=virtual%2Fthreaded%2Finspector%2Ftracing%2Ftimeline-js%2Ftimeline-runtime-stats.html

Original issue's description:
> Revert of DevTools: fix aggregated donut chart cache population (patchset #1 id:1 of https://codereview.chromium.org/2840463003/ )
> 
> Reason for revert:
> Suspected cause of failure of virtual/threaded/inspector/tracing/timeline-js/timeline-runtime-stats.html in https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win7%20(dbg)/builds/9644
> 
> Original issue's description:
> > DevTools: fix aggregated donut chart cache population
> > 
> > The check for stats cache availablity was made on the first task in the main thread
> > tasks list. If the first task happens to be filtered out, it never gets cache built for
> > it. Later the cache presence check would look for a cache on the first task, never find
> > it and forces recaching.
> > 
> > BUG=714934
> > 
> > Review-Url: https://codereview.chromium.org/2840463003
> > Cr-Commit-Position: refs/heads/master@{#467114}
> > Committed: https://chromium.googlesource.com/chromium/src/+/755b1656f38d135013f24ddd8b6ec046874beed2
> 
> TBR=pfeldman@chromium.org,alph@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=714934
> 
> Review-Url: https://codereview.chromium.org/2839083002
> Cr-Commit-Position: refs/heads/master@{#467223}
> Committed: https://chromium.googlesource.com/chromium/src/+/65df576fce3007b62084239cc8e37a45aea0368f

TBR=pfeldman@chromium.org,sashab@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=714934
Review-Url: https://codereview.chromium.org/2851823002
Cr-Commit-Position: refs/heads/master@{#468119}
Committed: https://chromium.googlesource.com/chromium/src/+/2e2708b5c1cb31e5d4dde1f105af1c473795d3b9

[alph, 2017-04-28 18:59:28]

The CQ bit was checked by alph@chromium.org

[alph, 2017-04-28 18:59:28]

Created Reland of DevTools: fix aggregated donut chart cache population

[commit-bot: I haz the power, 2017-04-28 19:00:46]

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, 2017-04-28 20:47:05]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493405968425550, "parent_rev":
"fde86224c05a8bb41576591b31d7a2058ed32cb1", "commit_rev":
"2e2708b5c1cb31e5d4dde1f105af1c473795d3b9"}

[commit-bot: I haz the power, 2017-04-28 20:47:14]

Description was changed from

==========
Reland of DevTools: fix aggregated donut chart cache population (patchset #1
id:1 of https://codereview.chromium.org/2839083002/ )

Reason for revert:
The patch has noting to do with the failing test. In fact if you look at the
flakiness dashboard the test is very flaky there:

https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType...

Original issue's description:
> Revert of DevTools: fix aggregated donut chart cache population (patchset #1
id:1 of https://codereview.chromium.org/2840463003/ )
> 
> Reason for revert:
> Suspected cause of failure of
virtual/threaded/inspector/tracing/timeline-js/timeline-runtime-stats.html in
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win7%20(dbg)/b...
> 
> Original issue's description:
> > DevTools: fix aggregated donut chart cache population
> > 
> > The check for stats cache availablity was made on the first task in the main
thread
> > tasks list. If the first task happens to be filtered out, it never gets
cache built for
> > it. Later the cache presence check would look for a cache on the first task,
never find
> > it and forces recaching.
> > 
> > BUG=714934
> > 
> > Review-Url: https://codereview.chromium.org/2840463003
> > Cr-Commit-Position: refs/heads/master@{#467114}
> > Committed:
https://chromium.googlesource.com/chromium/src/+/755b1656f38d135013f24ddd8b6e...
> 
> TBR=pfeldman@chromium.org,alph@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=714934
> 
> Review-Url: https://codereview.chromium.org/2839083002
> Cr-Commit-Position: refs/heads/master@{#467223}
> Committed:
https://chromium.googlesource.com/chromium/src/+/65df576fce3007b62084239cc8e3...

TBR=pfeldman@chromium.org,sashab@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=714934
==========

to

==========
Reland of DevTools: fix aggregated donut chart cache population (patchset #1
id:1 of https://codereview.chromium.org/2839083002/ )

Reason for revert:
The patch has noting to do with the failing test. In fact if you look at the
flakiness dashboard the test is very flaky there:

https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType...

Original issue's description:
> Revert of DevTools: fix aggregated donut chart cache population (patchset #1
id:1 of https://codereview.chromium.org/2840463003/ )
> 
> Reason for revert:
> Suspected cause of failure of
virtual/threaded/inspector/tracing/timeline-js/timeline-runtime-stats.html in
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win7%20(dbg)/b...
> 
> Original issue's description:
> > DevTools: fix aggregated donut chart cache population
> > 
> > The check for stats cache availablity was made on the first task in the main
thread
> > tasks list. If the first task happens to be filtered out, it never gets
cache built for
> > it. Later the cache presence check would look for a cache on the first task,
never find
> > it and forces recaching.
> > 
> > BUG=714934
> > 
> > Review-Url: https://codereview.chromium.org/2840463003
> > Cr-Commit-Position: refs/heads/master@{#467114}
> > Committed:
https://chromium.googlesource.com/chromium/src/+/755b1656f38d135013f24ddd8b6e...
> 
> TBR=pfeldman@chromium.org,alph@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=714934
> 
> Review-Url: https://codereview.chromium.org/2839083002
> Cr-Commit-Position: refs/heads/master@{#467223}
> Committed:
https://chromium.googlesource.com/chromium/src/+/65df576fce3007b62084239cc8e3...

TBR=pfeldman@chromium.org,sashab@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=714934

Review-Url: https://codereview.chromium.org/2851823002
Cr-Commit-Position: refs/heads/master@{#468119}
Committed:
https://chromium.googlesource.com/chromium/src/+/2e2708b5c1cb31e5d4dde1f105af...
==========

[commit-bot: I haz the power, 2017-04-28 20:47:16]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/2e2708b5c1cb31e5d4dde1f105af...