Reland of Timeline: extract and rename TracingModelLoader into a file of its own

Reland of Timeline: extract and rename TracingModelLoader into a file of its own (patchset #1 id:1 of https://codereview.chromium.org/1752453002/ )

Reason for revert:
Reverting of revert, it doesn't look to me this was the culprit in layout test failures.

Original issue's description:
> Revert of Timeline: extract and rename TracingModelLoader into a file of its own (patchset #4 id:60001 of https://codereview.chromium.org/1739193003/ )
>
> Reason for revert:
> Possible cause behind failure in webkit-tests on WebKit Mac10.11 and WebKit Mac10.11 (retina).
>
> Original issue's description:
> > Timeline: extract and rename TracingModelLoader into a file of its own
> >
> > This just extracts TimelineLoader with the aim of later  refactoring
> > it to untangle timeline lifecycle events from TimelineModel.
> >
> > Committed: https://crrev.com/b994e8b0a8af48aca6aa2182b5e8157b4873c0e9
> > Cr-Commit-Position: refs/heads/master@{#378109}
>
> TBR=alph@chromium.org,caseq@chromium.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
>
> Committed: https://crrev.com/c4ffa58b1a2c1eb0484dc21b68632e96c070652c
> Cr-Commit-Position: refs/heads/master@{#378291}

TBR=alph@chromium.org,nektar@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/d00fd87bd29b1f7d43f39465d9f6fc053c82dc73
Cr-Commit-Position: refs/heads/master@{#378464}

[caseq, 2016-03-01 17:24:40]

Created Reland of Timeline: extract and rename TracingModelLoader into a file of
its own

[commit-bot: I haz the power, 2016-03-01 17:25:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1754713002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1754713002/1

[commit-bot: I haz the power, 2016-03-01 17:25:40]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-01 17:26:49]

Description was changed from

==========
Reland of Timeline: extract and rename TracingModelLoader into a file of its own
(patchset #1 id:1 of https://codereview.chromium.org/1752453002/ )

Reason for revert:
Reverting of revert, it doesn't look to me this was the culprit in layout test
failures.

Original issue's description:
> Revert of Timeline: extract and rename TracingModelLoader into a file of its
own (patchset #4 id:60001 of https://codereview.chromium.org/1739193003/ )
> 
> Reason for revert:
> Possible cause behind failure in webkit-tests on WebKit Mac10.11 and WebKit
Mac10.11 (retina).
> 
> Original issue's description:
> > Timeline: extract and rename TracingModelLoader into a file of its own
> >
> > This just extracts TimelineLoader with the aim of later  refactoring
> > it to untangle timeline lifecycle events from TimelineModel.
> >
> > Committed: https://crrev.com/b994e8b0a8af48aca6aa2182b5e8157b4873c0e9
> > Cr-Commit-Position: refs/heads/master@{#378109}
> 
> TBR=alph@chromium.org,caseq@chromium.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> 
> Committed: https://crrev.com/c4ffa58b1a2c1eb0484dc21b68632e96c070652c
> Cr-Commit-Position: refs/heads/master@{#378291}

TBR=alph@chromium.org,nektar@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
==========

to

==========
Reland of Timeline: extract and rename TracingModelLoader into a file of its own
(patchset #1 id:1 of https://codereview.chromium.org/1752453002/ )

Reason for revert:
Reverting of revert, it doesn't look to me this was the culprit in layout test
failures.

Original issue's description:
> Revert of Timeline: extract and rename TracingModelLoader into a file of its
own (patchset #4 id:60001 of https://codereview.chromium.org/1739193003/ )
>
> Reason for revert:
> Possible cause behind failure in webkit-tests on WebKit Mac10.11 and WebKit
Mac10.11 (retina).
>
> Original issue's description:
> > Timeline: extract and rename TracingModelLoader into a file of its own
> >
> > This just extracts TimelineLoader with the aim of later  refactoring
> > it to untangle timeline lifecycle events from TimelineModel.
> >
> > Committed: https://crrev.com/b994e8b0a8af48aca6aa2182b5e8157b4873c0e9
> > Cr-Commit-Position: refs/heads/master@{#378109}
>
> TBR=alph@chromium.org,caseq@chromium.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
>
> Committed: https://crrev.com/c4ffa58b1a2c1eb0484dc21b68632e96c070652c
> Cr-Commit-Position: refs/heads/master@{#378291}

TBR=alph@chromium.org,nektar@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/d00fd87bd29b1f7d43f39465d9f6fc053c82dc73
Cr-Commit-Position: refs/heads/master@{#378464}
==========

[commit-bot: I haz the power, 2016-03-01 17:26:50]

Patchset 1 (id:??) landed as
https://crrev.com/d00fd87bd29b1f7d43f39465d9f6fc053c82dc73
Cr-Commit-Position: refs/heads/master@{#378464}