cc: Change ClipNode::applies_local_clip to a clip_type enum

This change is in preparation for adding "expanding" clip nodes,
which will involve adding a new ClipType.

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
BUG=653631

Review-Url: https://codereview.chromium.org/2437923002
Cr-Commit-Position: refs/heads/master@{#427082}
12 files changed