Chromium side of merge 39453:39501....

Chromium side of merge 39453:39501.

Includes new baselines for fast/transforms/identity-matrix-expected.html, which
was edited slightly, and fast/backgrounds/opacity-on-document-element.html,
which is new and looks correct.

BUG=none
TEST=none

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=7513

[Pam (message me for reviews), 2008-12-30 17:41:47]

XCode changes to follow separately.

Two layout tests actually fail with this, cross-frame-access-protocol.html and
cross-frame-access-protocol-explicit-domain.html.  I'm suspicious that it's a
cert problem on my machine rather than a code problem, so I'm going to let the
buildbot try it out for me.  I'll fix the tests_fixable promptly if needed.

[brettw, 2008-12-30 17:50:21]

LGTM