[SPv2] Refactor PaintArtifactorCompositor root node creation

[SPv2] Refactor PaintArtifactorCompositor root node creation

This CL sets up static conversion for root blink property nodes into the
hardcoded cc property nodes number 1 (a.k.a. secondary root).

Now we also enforce that every blink-created property node can never refer to
nullptr nodes.

BUG=645615
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Committed: https://crrev.com/c2fccd350841d0d60631a7196c1bb9b0bf838255
Cr-Commit-Position: refs/heads/master@{#432677}

[trchen, 2016-11-16 03:28:48]

Description was changed from

==========
[SPv2] Refactor PaintArtifactorCompositor root node creation

This CL sets up static conversion for root blink property nodes into the
hardcoded cc property nodes number 1 (a.k.a. secondary root).

Now we also enforce that every blink-created property node can never refer to
nullptr nodes.

BUG=645615
==========

to

==========
[SPv2] Refactor PaintArtifactorCompositor root node creation

This CL sets up static conversion for root blink property nodes into the
hardcoded cc property nodes number 1 (a.k.a. secondary root).

Now we also enforce that every blink-created property node can never refer to
nullptr nodes.

BUG=645615
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[trchen, 2016-11-16 03:30:43]

trchen@chromium.org changed reviewers:
+ pdr@chromium.org

[trchen, 2016-11-16 03:30:44]

Disallow nullptr property nodes everywhere!

[pdr., 2016-11-16 03:48:20]

LGTM, nice cleanup

[trchen, 2016-11-16 19:46:57]

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

[commit-bot: I haz the power, 2016-11-16 19:47:28]

Dry run: 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, 2016-11-16 23:21:12]

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

[commit-bot: I haz the power, 2016-11-16 23:21:16]

Dry run: This issue passed the CQ dry run.

[trchen, 2016-11-16 23:49:39]

The CQ bit was checked by trchen@chromium.org

[commit-bot: I haz the power, 2016-11-16 23:51:25]

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, 2016-11-17 00:31:25]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-17 00:41:54]

Description was changed from

==========
[SPv2] Refactor PaintArtifactorCompositor root node creation

This CL sets up static conversion for root blink property nodes into the
hardcoded cc property nodes number 1 (a.k.a. secondary root).

Now we also enforce that every blink-created property node can never refer to
nullptr nodes.

BUG=645615
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
[SPv2] Refactor PaintArtifactorCompositor root node creation

This CL sets up static conversion for root blink property nodes into the
hardcoded cc property nodes number 1 (a.k.a. secondary root).

Now we also enforce that every blink-created property node can never refer to
nullptr nodes.

BUG=645615
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Committed: https://crrev.com/c2fccd350841d0d60631a7196c1bb9b0bf838255
Cr-Commit-Position: refs/heads/master@{#432677}
==========

[commit-bot: I haz the power, 2016-11-17 00:41:55]

Patchset 1 (id:??) landed as
https://crrev.com/c2fccd350841d0d60631a7196c1bb9b0bf838255
Cr-Commit-Position: refs/heads/master@{#432677}