cc : Split TransformTree::ComputeTransform

cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Committed: https://crrev.com/4a2bde300742723c46df1f1917636726d46389c7
Cr-Commit-Position: refs/heads/master@{#408409}

[jaydasika, 2016-07-27 00:19:54]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform during updating transform tree,
which will be eventually deleted.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform during updating transform tree,
which will be eventually deleted.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

[jaydasika, 2016-07-27 00:20:16]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform during updating transform tree,
which will be eventually deleted.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform during updating transform tree,
which will be eventually deleted.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

[jaydasika, 2016-07-27 00:21:01]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform during updating transform tree,
which will be eventually deleted.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform while updating transform tree,
which will be eventually deleted.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

[jaydasika, 2016-07-27 00:21:21]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform while updating transform tree,
which will be eventually deleted.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform while updating transform tree,
which will be deleted eventually.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

[jaydasika, 2016-07-27 00:25:26]

jaydasika@chromium.org changed reviewers:
+ ajuma@chromium.org, sunxd@chromium.org, weiliangc@chromium.org

[jaydasika, 2016-07-27 00:25:27]

PTAL

[jaydasika, 2016-07-27 15:44:53]

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

[commit-bot: I haz the power, 2016-07-27 15:45:10]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[ajuma, 2016-07-27 15:57:11]

Generally looks good, just some nits about ComputeTransformFromSourceToParent:

https://codereview.chromium.org/2180223005/diff/1/cc/trees/property_tree.cc
File cc/trees/property_tree.cc (right):

https://codereview.chromium.org/2180223005/diff/1/cc/trees/property_tree.cc#n...
cc/trees/property_tree.cc:161: bool
TransformTree::ComputeTransformFromSourceToParent(
Since this currently has essentially the same implementation as
ComputeTransform, can the common parts go into a helper function for now?

https://codereview.chromium.org/2180223005/diff/1/cc/trees/property_tree.h
File cc/trees/property_tree.h (right):

https://codereview.chromium.org/2180223005/diff/1/cc/trees/property_tree.h#ne...
cc/trees/property_tree.h:159: gfx::Transform* transform) const;
It'd be good if there was some way to enforce that this is used only for
source-to-parent transforms rather than arbitrary transforms. One idea: rename
this ComputeTranslation() with a comment that this can only be called between
pairs of nodes where the transform between nodes is a 2d translation, and then
DCHECK that the computed transform is indeed a 2d translation before returning?

[commit-bot: I haz the power, 2016-07-27 16:31:14]

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

[commit-bot: I haz the power, 2016-07-27 16:31:17]

Dry run: This issue passed the CQ dry run.

[jaydasika, 2016-07-27 18:40:30]

Patchset #3 (id:40001) has been deleted

[jaydasika, 2016-07-27 18:42:24]

https://codereview.chromium.org/2180223005/diff/1/cc/trees/property_tree.cc
File cc/trees/property_tree.cc (right):

https://codereview.chromium.org/2180223005/diff/1/cc/trees/property_tree.cc#n...
cc/trees/property_tree.cc:161: bool
TransformTree::ComputeTransformFromSourceToParent(
On 2016/07/27 15:57:11, ajuma wrote:
> Since this currently has essentially the same implementation as
> ComputeTransform, can the common parts go into a helper function for now?

Done.

https://codereview.chromium.org/2180223005/diff/1/cc/trees/property_tree.h
File cc/trees/property_tree.h (right):

https://codereview.chromium.org/2180223005/diff/1/cc/trees/property_tree.h#ne...
cc/trees/property_tree.h:159: gfx::Transform* transform) const;
On 2016/07/27 15:57:11, ajuma wrote:
> It'd be good if there was some way to enforce that this is used only for
> source-to-parent transforms rather than arbitrary transforms. One idea: rename
> this ComputeTranslation() with a comment that this can only be called between
> pairs of nodes where the transform between nodes is a 2d translation, and then
> DCHECK that the computed transform is indeed a 2d translation before
returning?

Done.

[jaydasika, 2016-07-27 18:42:29]

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

[commit-bot: I haz the power, 2016-07-27 18:42:40]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[jaydasika, 2016-07-27 18:43:37]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTransformsFromSourceToParent.

With this CL, TransformTree::ComputeTransforms is only called by tests
and for computing target space transform while updating transform tree,
which will be deleted eventually.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

[commit-bot: I haz the power, 2016-07-27 18:43:56]

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

[commit-bot: I haz the power, 2016-07-27 18:43:57]

Dry run: Try jobs failed on following builders:
  linux_blink_rel on master.tryserver.blink (JOB_FAILED, no build URL)

[jaydasika, 2016-07-27 18:44:11]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

[jaydasika, 2016-07-27 18:45:23]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

[jaydasika, 2016-07-27 18:45:47]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
==========

[ajuma, 2016-07-27 19:00:32]

lgtm

https://codereview.chromium.org/2180223005/diff/60001/cc/trees/property_tree.h
File cc/trees/property_tree.h (right):

https://codereview.chromium.org/2180223005/diff/60001/cc/trees/property_tree....
cc/trees/property_tree.h:157: bool ComputeTranslation(int source_id,
Please add a comment explaining what this does and the conditions that source_id
and dest_id must satisfy (e.g. that the transform between them must be at most a
translation).

[jaydasika, 2016-07-27 19:22:18]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

[jaydasika, 2016-07-27 19:22:48]

The CQ bit was checked by jaydasika@chromium.org

[jaydasika, 2016-07-27 19:22:49]

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/2180223005/#ps80001
(title: "comment")

[commit-bot: I haz the power, 2016-07-27 19:23:21]

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, 2016-07-27 19:23:22]

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

[commit-bot: I haz the power, 2016-07-27 19:23:23]

Your CL was about to rely on recently removed CQ feature(s):
 * master.tryserver.blink builder linux_blink_rel was renamed to
linux_precise_blink_rel (http://crbug.com/590036)

[jaydasika, 2016-07-27 19:23:48]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

[jaydasika, 2016-07-27 19:24:27]

The CQ bit was checked by jaydasika@chromium.org

[commit-bot: I haz the power, 2016-07-27 19:24:52]

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, 2016-07-27 20:35:16]

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

[commit-bot: I haz the power, 2016-07-27 20:35:18]

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

[jaydasika, 2016-07-27 20:38:30]

The CQ bit was checked by jaydasika@chromium.org

[commit-bot: I haz the power, 2016-07-27 20:38:42]

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, 2016-07-27 21:42:58]

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

[commit-bot: I haz the power, 2016-07-27 21:42:59]

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

[jaydasika, 2016-07-28 02:17:18]

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

[commit-bot: I haz the power, 2016-07-28 02:17:28]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[jaydasika, 2016-07-28 02:18:04]

https://codereview.chromium.org/2180223005/diff/100001/cc/trees/property_tree.cc
File cc/trees/property_tree.cc (right):

https://codereview.chromium.org/2180223005/diff/100001/cc/trees/property_tree...
cc/trees/property_tree.cc:166:
transform->IsApproximatelyIdentityOrTranslation(SkDoubleToMScalar(1e-4)));
Had to change this as some browser tests are failing on android.

[commit-bot: I haz the power, 2016-07-28 03:30:20]

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

[commit-bot: I haz the power, 2016-07-28 03:30:21]

Dry run: This issue passed the CQ dry run.

[ajuma, 2016-07-28 14:21:40]

On 2016/07/28 02:18:04, jaydasika wrote:
>
https://codereview.chromium.org/2180223005/diff/100001/cc/trees/property_tree.cc
> File cc/trees/property_tree.cc (right):
> 
>
https://codereview.chromium.org/2180223005/diff/100001/cc/trees/property_tree...
> cc/trees/property_tree.cc:166:
> transform->IsApproximatelyIdentityOrTranslation(SkDoubleToMScalar(1e-4)));
> Had to change this as some browser tests are failing on android.

Still lgtm

[jaydasika, 2016-07-28 16:15:04]

The CQ bit was checked by jaydasika@chromium.org

[commit-bot: I haz the power, 2016-07-28 16:15:18]

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, 2016-07-28 17:22:30]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

[commit-bot: I haz the power, 2016-07-28 17:22:31]

Committed patchset #5 (id:100001)

[commit-bot: I haz the power, 2016-07-28 17:25:33]

Description was changed from

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

to

==========
cc : Split TransformTree::ComputeTransform

ComputeTransform is too general as we can call it with any transform nodes.
To to able to effectively use the new transforms caching system, we have
to know more information. I added ComputeTransformsToTarget for this
reason. This CL adds ComputeTransformsFromTarget and
ComputeTranslation.

With this CL, TransformTree::ComputeTransforms is only called by tests,
for computing target space transform while updating transform tree,
and from these new functions.

Also changed the return value of TransformTree::CombineTransformBetween
from bool to void as it always returns true.

BUG=622372
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Committed: https://crrev.com/4a2bde300742723c46df1f1917636726d46389c7
Cr-Commit-Position: refs/heads/master@{#408409}
==========

[commit-bot: I haz the power, 2016-07-28 17:25:35]

Patchset 5 (id:??) landed as
https://crrev.com/4a2bde300742723c46df1f1917636726d46389c7
Cr-Commit-Position: refs/heads/master@{#408409}