Remove PaintInfo's paintingRoot

Remove PaintInfo's paintingRoot

PaintInfo had a paintingRoot member for supporting drawing a single
layout object (including descendants). This complexity is spread
throughout the painting code and only exists to support drag and drop
drag images:
https://chromium.googlesource.com/chromium/src/+/65e7e9d4860e50bb677228f0b83848cce208eb76

This patch switches to directly painting LayoutObjects and removes the
complex paintingRoot code.

ClusterTelemetry results: 0.5% record time savings:
https://storage.cloud.google.com/cluster-telemetry/tasks/chromium_perf_runs/pdr-20160118203222/html/index.html

BUG=577004
Committed: https://crrev.com/63c9596d206c896b35ae8a5bff4db73847f62f33
Cr-Commit-Position: refs/heads/master@{#370334}

[pdr., 2016-01-18 20:31:38]

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

[commit-bot: I haz the power, 2016-01-18 20:32:23]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1602513004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1602513004/1

[commit-bot: I haz the power, 2016-01-18 21:39:39]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-01-18 21:39:40]

Dry run: This issue passed the CQ dry run.

[pdr., 2016-01-18 22:09:05]

Description was changed from

==========
Remove PaintInfo's paintingRoot

PaintInfo had a paintingRoot member for supporting drawing a single
layout object (including descendants). This complexity is spread
throughout the painting code and only exists to support drag and drop
drag images:
https://chromium.googlesource.com/chromium/src/+/65e7e9d4860e50bb677228f0b838...

This patch switches to directly painting LayoutObjects and removes the
complex paintingRoot code.

ClusterTelemetry results: TBD

BUG=577004
==========

to

==========
Remove PaintInfo's paintingRoot

PaintInfo had a paintingRoot member for supporting drawing a single
layout object (including descendants). This complexity is spread
throughout the painting code and only exists to support drag and drop
drag images:
https://chromium.googlesource.com/chromium/src/+/65e7e9d4860e50bb677228f0b838...

This patch switches to directly painting LayoutObjects and removes the
complex paintingRoot code.

ClusterTelemetry results: 0.5% record time savings:
https://storage.cloud.google.com/cluster-telemetry/tasks/chromium_perf_runs/p...

BUG=577004
==========

[pdr., 2016-01-19 17:49:22]

pdr@chromium.org changed reviewers:
+ chrishtr@chromium.org, wangxianzhu@chromium.org

[chrishtr, 2016-01-19 18:29:22]

Looks like a nice improvement to me.

https://codereview.chromium.org/1602513004/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/frame/LocalFrame.cpp (right):

https://codereview.chromium.org/1602513004/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/frame/LocalFrame.cpp:676: TransformRecorder
transformRecorder(pictureBuilder.context(), *this, transform);
The code here looks like it duplicates paintIntoDragImage. Refactor into a
helper.

[pdr., 2016-01-19 23:29:22]

https://codereview.chromium.org/1602513004/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/frame/LocalFrame.cpp (right):

https://codereview.chromium.org/1602513004/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/frame/LocalFrame.cpp:676: TransformRecorder
transformRecorder(pictureBuilder.context(), *this, transform);
On 2016/01/19 at 18:29:21, chrishtr wrote:
> The code here looks like it duplicates paintIntoDragImage. Refactor into a
helper.

Good idea. This required some invasive refactoring because there are two ways
the context is used. I think the code ended up in a nicer place.

[pdr., 2016-01-19 23:29:25]

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

[commit-bot: I haz the power, 2016-01-19 23:30:01]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1602513004/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1602513004/40001

[chrishtr, 2016-01-19 23:46:45]

lgtm

[Xianzhu, 2016-01-20 00:25:18]

https://codereview.chromium.org/1602513004/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/frame/LocalFrame.cpp (right):

https://codereview.chromium.org/1602513004/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/frame/LocalFrame.cpp:676: // FIXME(pdr): This
will also paint the background if the object contains transparency. We can
Nit: s/FIXME/TODO/ ?

[pdr., 2016-01-20 00:31:53]

On 2016/01/20 at 00:25:18, wangxianzhu wrote:
>
https://codereview.chromium.org/1602513004/diff/40001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/core/frame/LocalFrame.cpp (right):
> 
>
https://codereview.chromium.org/1602513004/diff/40001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/frame/LocalFrame.cpp:676: // FIXME(pdr): This
will also paint the background if the object contains transparency. We can
> Nit: s/FIXME/TODO/ ?

Done.

I also added a TODO about two bugs I found when working on this patch
(crbug.com/579153, crbug.com/579158). These were both broken before this patch,
just documenting that they can be fixed fairly easily.

[pdr., 2016-01-20 00:31:59]

The CQ bit was checked by pdr@chromium.org

[pdr., 2016-01-20 00:31:59]

The patchset sent to the CQ was uploaded after l-g-t-m from
chrishtr@chromium.org
Link to the patchset: https://codereview.chromium.org/1602513004/#ps60001
(title: "Update commentary")

[commit-bot: I haz the power, 2016-01-20 00:34:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1602513004/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1602513004/60001

[commit-bot: I haz the power, 2016-01-20 03:06:09]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-01-20 03:06:10]

Try jobs failed on following builders:
  android_arm64_dbg_recipe on tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_arm6...)

[pdr., 2016-01-20 03:16:34]

The CQ bit was checked by pdr@chromium.org

[commit-bot: I haz the power, 2016-01-20 03:18:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1602513004/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1602513004/60001

[commit-bot: I haz the power, 2016-01-20 03:27:52]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-01-20 03:27:53]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[pdr., 2016-01-20 04:22:00]

The CQ bit was checked by pdr@chromium.org

[pdr., 2016-01-20 04:22:00]

The patchset sent to the CQ was uploaded after l-g-t-m from
chrishtr@chromium.org
Link to the patchset: https://codereview.chromium.org/1602513004/#ps80001
(title: "Rebase for landing")

[commit-bot: I haz the power, 2016-01-20 04:22:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1602513004/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1602513004/80001

[commit-bot: I haz the power, 2016-01-20 06:38:57]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2016-01-20 06:39:38]

Description was changed from

==========
Remove PaintInfo's paintingRoot

PaintInfo had a paintingRoot member for supporting drawing a single
layout object (including descendants). This complexity is spread
throughout the painting code and only exists to support drag and drop
drag images:
https://chromium.googlesource.com/chromium/src/+/65e7e9d4860e50bb677228f0b838...

This patch switches to directly painting LayoutObjects and removes the
complex paintingRoot code.

ClusterTelemetry results: 0.5% record time savings:
https://storage.cloud.google.com/cluster-telemetry/tasks/chromium_perf_runs/p...

BUG=577004
==========

to

==========
Remove PaintInfo's paintingRoot

PaintInfo had a paintingRoot member for supporting drawing a single
layout object (including descendants). This complexity is spread
throughout the painting code and only exists to support drag and drop
drag images:
https://chromium.googlesource.com/chromium/src/+/65e7e9d4860e50bb677228f0b838...

This patch switches to directly painting LayoutObjects and removes the
complex paintingRoot code.

ClusterTelemetry results: 0.5% record time savings:
https://storage.cloud.google.com/cluster-telemetry/tasks/chromium_perf_runs/p...

BUG=577004

Committed: https://crrev.com/63c9596d206c896b35ae8a5bff4db73847f62f33
Cr-Commit-Position: refs/heads/master@{#370334}
==========

[commit-bot: I haz the power, 2016-01-20 06:39:39]

Patchset 5 (id:??) landed as
https://crrev.com/63c9596d206c896b35ae8a5bff4db73847f62f33
Cr-Commit-Position: refs/heads/master@{#370334}

[pdr., 2016-01-20 06:56:07]

A revert of this CL (patchset #5 id:80001) has been created in
https://codereview.chromium.org/1610063002/ by pdr@chromium.org.

The reason for reverting is: Broke oilpan and closed the tree:
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Oilpan...

I'll fix this tomorrow and reland..