editing/pasteboard/paste-noscript.html ASSERTs in force composting mode

This CL adds a new legal transition in the DocumentLifecycle state machine to
let us synchronously recalc style in a post layout task. Conceptually, that
doesn't make a whole lot of sense because nothing in layout should dirty style
information, but that appears to happen in this test.

We can work to remove this transition from the state machine in the future.

R=ojan@chromium.org
BUG=363844

Review URL: https://codereview.chromium.org/242423005

git-svn-id: svn://svn.chromium.org/blink/trunk@171991 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Delete CompositingProperties.

This tries to separate out the properties that are updating
during compositing, but in the process leads to worse bit packing
and is just confusing because the code doesn't do anything.
We could add comments before each of these properties and
have the same benefit.

Eventually, we should probably assert that compositing is
up to date in the getters for these properties.

Review URL: https://codereview.chromium.org/242493004

git-svn-id: svn://svn.chromium.org/blink/trunk@171992 bbb929c8-8fbe-4397-9dbb-9b2b20218538