Implement compositing bounds in CompositingDisplayItem

Implement compositing bounds in CompositingDisplayItem

This patch implements compositing bounds and plumbs them through to cc.
With this patch we pass the following additional tests:
LayoutTests/svg/zoom/page/zoom-mask-with-percentages.svg
LayoutTests/svg/transforms/text-with-mask-with-svg-transform.svg
LayoutTests/svg/custom/absolute-sized-content-with-resources.xhtml
LayoutTests/svg/custom/mask-excessive-malloc.svg
LayoutTests/svg/batik/masking/maskRegions.svg

Because there are only a few new passing tests I would like to wait
until clipping is supported to add any of these directories to our
virtual test suite.

This patch depends on the following chromium-side patch:
https://codereview.chromium.org/952123002

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=190876

[pdr., 2015-02-25 18:27:35]

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

[ajuma, 2015-02-25 18:35:36]

lgtm

[pdr., 2015-02-25 22:33:59]

The CQ bit was checked by pdr@chromium.org

[commit-bot: I haz the power, 2015-02-25 22:35:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/960483002/1

[pdr., 2015-02-25 23:17:32]

The CQ bit was unchecked by pdr@chromium.org

[pdr., 2015-02-25 23:18:05]

The CQ bit was checked by pdr@chromium.org

[pdr., 2015-02-25 23:18:05]

The patchset sent to the CQ was uploaded after l-g-t-m from ajuma@chromium.org
Link to the patchset: https://codereview.chromium.org/960483002/#ps20001 (title:
"Rebase from space")

[commit-bot: I haz the power, 2015-02-25 23:19:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/960483002/20001

[commit-bot: I haz the power, 2015-02-26 01:48:03]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=190876