Add ink drop ripple to status tray

Add ink drop ripple to status tray

This is still not handling view resizes that happen when an ink drop is
active (e.g., in status tray). A workaround is implemented, but proper
fix would need a follow-up CL.

This CL also changes round rect mask to take insets instead of bounds so
that there would be no need to update mask bounds when size of host view
is updated.

BUG=612544
TEST=manual

Review-Url: https://codereview.chromium.org/2510603003
Cr-Commit-Position: refs/heads/master@{#433113}
(cherry picked from commit c109436f07a06f711d50c982e2284f1460abd8a9)

[mohsen, 2016-11-21 20:47:09]

Committed patchset #1 (id:1) to pending queue manually as
2fd548fc750d0cade0738f9747ad255ce89d8a45.