Fix ApproximatelyEqual for transforms

Fix ApproximatelyEqual for transforms

I subtly broke this in https://codereview.chromium.org/1071803003. Due
to a cut and paste error, we were never updating |delta|.

Consequently, I missed a regression due to my property trees skipping:
I wasn't forcing a rebuild when contents scale or content bounds
changed (and this was required). I've fixed that in this CL as well.

BUG=471786
Committed: https://crrev.com/9a706e68a90749d54e336829ae759a56931ccf31
Cr-Commit-Position: refs/heads/master@{#326827}

[Ian Vollick, 2015-04-24 17:22:06]

vollick@chromium.org changed reviewers:
+ ajuma@chromium.org

[ajuma, 2015-04-24 17:23:43]

lgtm

[ajuma, 2015-04-24 17:25:31]

The CQ bit was checked by ajuma@chromium.org

[commit-bot: I haz the power, 2015-04-24 17:25:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1105933002/1

[commit-bot: I haz the power, 2015-04-24 17:30:56]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-24 17:31:42]

Patchset 1 (id:??) landed as
https://crrev.com/9a706e68a90749d54e336829ae759a56931ccf31
Cr-Commit-Position: refs/heads/master@{#326827}