RLZTracker refactoring/cleanup

* Introduced separate RLZTrackerDelegate to provide test impl.
* API calls now simply schedule the task on SequencedWorkerPool
* acquire lock when clearing cache in ClearnupRlz

A few extra notes:
 * I removed GetAccessPointRlz{On/NotOn}IoThread because
   we no longer mix methods between threads.
 * I reordered methods only in headers. I kept the order in .cc file
   to make the reviewing easier. I'll reorder the method body in followup CL.

BUG=261377

Review URL: https://codereview.chromium.org/26771002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228333 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228333
Follow-ups/Tweaks for Embedded Flash Fullscreen.

1. Added mouse lock support for the embedded flash fullscreen widget using the existing Flash-privileged mechanism.
2. Removed the redundant "Press Esc to Exit Fullscreen" balloon pop-up, in favor of Flash's built-in message.
3. Fixed bug where the status bubble/tooltip (at lower-left) was not being hidden while in fullscreen mode.

Testing: Ran unit tests.  Manually confirmed all of the above work as intended both with *and* without the --embed-flash-fullscreen command-line flag.  Tested on Linux/Win Aura, Mac, and Win non-Aura.

BUG=290403,256870

Review URL: https://codereview.chromium.org/26803002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228334 0039d316-1c4b-4281-b951-d872f2087c98
Features:
- Add support in API for sourceId, destinationId.
- Add support for sending and receiving binary messages (required for auth)

Fixes/refactorings:
- Refactor APIs to be generic on message type to avoid code duplicaton.
- Factor out conversion code between MessageInfo API object and CastMessage
proto to share between impl and unit tests.


BUG=295843

Review URL: https://codereview.chromium.org/26878002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228335 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228335