Web Animations: Add InterpolableAnimatableValue class.

This patch introduces InterpolableAnimatableValues, which are
InterpolableValues that wrap AnimatableValues. In a future patch, these values
will be used to support the legacy AnimatableValue pipeline within the new
InterpolableValue pipeline, which means we won't need to convert all value
logic across at the same time.

BUG=346495

Review URL: https://codereview.chromium.org/192733002

git-svn-id: svn://svn.chromium.org/blink/trunk@168902 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Oilpan: move WorkerThreadStartupData to the oilpan heap.

R=vegorov@chromium.org,tkent@chromium.org
BUG=340522

Review URL: https://codereview.chromium.org/191003010

git-svn-id: svn://svn.chromium.org/blink/trunk@168903 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[webcrypto] Change the order of usages in Key.usages.

Blink's implementation used to list them in lexicographic order. Changed to match the order defined by the spec in:
https://dvcs.w3.org/hg/webcrypto-api/rev/ca494eeb8ddf

BUG=245025

Review URL: https://codereview.chromium.org/194323002

git-svn-id: svn://svn.chromium.org/blink/trunk@168904 bbb929c8-8fbe-4397-9dbb-9b2b20218538