cc : Move screen space scale factor to root transform node

cc : Move screen space scale factor to root transform node

This CL computes the screen space scale factor which is
combined form scale factors of device transform, device
scale factor and page scale factor(if required), and stores
it on the root transform node as its surface contents scale.
This also implicitly fixes a clipping bug.
TransformTree::ComputeTransforms(a, b) should return the
transform between a and b without the surface contents
scale. But, since screen space scale was baked into the
local transform of the contents root node (before this CL),
ComputeTransform(a, root) was having the scale baked in.
(and this caused the bug)

BUG=651584
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2408243002
Cr-Commit-Position: refs/heads/master@{#427366}
(cherry picked from commit 61fa0fb418a3f77665e0bc1be88ec5a2984c6dc6)

Committed: https://chromium.googlesource.com/chromium/src/+/b96a29859b70eea11eacefef82b25318d43700fc

[jaydasika, 2016-10-26 22:49:08]

Description was changed from

==========
cc : Move screen space scale factor to root transform node

This CL computes the screen space scale factor which is
combined form scale factors of device transform, device
scale factor and page scale factor(if required), and stores
it on the root transform node as its surface contents scale.
This also implicitly fixes a clipping bug.
TransformTree::ComputeTransforms(a, b) should return the
transform between a and b without the surface contents
scale. But, since screen space scale was baked into the
local transform of the contents root node (before this CL),
ComputeTransform(a, root) was having the scale baked in.
(and this caused the bug)

BUG=651584
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2408243002
Cr-Commit-Position: refs/heads/master@{#427366}
(cherry picked from commit 61fa0fb418a3f77665e0bc1be88ec5a2984c6dc6)
==========

to

==========
cc : Move screen space scale factor to root transform node

This CL computes the screen space scale factor which is
combined form scale factors of device transform, device
scale factor and page scale factor(if required), and stores
it on the root transform node as its surface contents scale.
This also implicitly fixes a clipping bug.
TransformTree::ComputeTransforms(a, b) should return the
transform between a and b without the surface contents
scale. But, since screen space scale was baked into the
local transform of the contents root node (before this CL),
ComputeTransform(a, root) was having the scale baked in.
(and this caused the bug)

BUG=651584
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2408243002
Cr-Commit-Position: refs/heads/master@{#427366}
(cherry picked from commit 61fa0fb418a3f77665e0bc1be88ec5a2984c6dc6)

Committed:
https://chromium.googlesource.com/chromium/src/+/b96a29859b70eea11eacefef82b2...
==========

[jaydasika, 2016-10-26 22:49:09]

Committed patchset #1 (id:1) manually as
b96a29859b70eea11eacefef82b25318d43700fc.

[jaydasika, 2016-10-27 21:02:19]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2454203002/ by jaydasika@chromium.org.

The reason for reverting is:
https://bugs.chromium.org/p/chromium/issues/detail?id=660047.