Connect WebMediaPlayer to WebContentDecryptionModule for EME WD

As support is added for EME WD, WebMediaPlayer needs to access the
connected CDM (set in HTMLMediaElement.setMediaKeys()). This change
adds the plumbing so that the current CDM can be determined by
WebMediaPlayer.

BUG=329582
TEST=new layout test passes

Review URL: https://codereview.chromium.org/113563003

git-svn-id: svn://svn.chromium.org/blink/trunk@164660 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix isCandidateForAnimationOnCompositorKeyframeMultipleCSSProperties

The test is super fragile as it relies on the value of some
CSSPropertyID which will change as people add more properties.
We unfortunately can't use some fixed values as it relies on using
a supported property whose CSSPropertyID will evolve over time.

This change just reverts the test to its state before:
https://codereview.chromium.org/68173013

Review URL: https://codereview.chromium.org/115403003

git-svn-id: svn://svn.chromium.org/blink/trunk@164661 bbb929c8-8fbe-4397-9dbb-9b2b20218538