[Sync] Create new top-level sync/ directory

[Sync] Create new top-level sync/ directory

Move sync .proto files to sync/protocol.  Update all references.

This begins the Great Sync Migration.

BUG=117585, 43624
TEST=

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=125967

[akalin, 2012-03-09 22:06:19]

+sky for search engines
+mmenke for net
+darin for top-level directory
+tim for everything

[mmenke, 2012-03-09 22:10:40]

net changes LGTM.

[darin (slow to review), 2012-03-09 22:32:29]

LGTM for src/sync/ creation.

[sky, 2012-03-09 23:36:49]

LGTM in the future feel free to TBR these sort of things.

[tim (not reviewing), 2012-03-10 00:06:25]

LGTM!

[commit-bot: I haz the power, 2012-03-10 00:19:13]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/akalin@chromium.org/9668028/10002

[commit-bot: I haz the power, 2012-03-10 00:19:49]

Can't apply patch for file chrome/chrome_browser_extensions.gypi.
While running patch -p1 --forward --force;
patching file chrome/chrome_browser_extensions.gypi
Hunk #1 FAILED at 11.
1 out of 1 hunk FAILED -- saving rejects to file
chrome/chrome_browser_extensions.gypi.rej