Make it clear what last_sync_timestamp actually tracks.  Update
last_sync_timestamp from the new_timestamp only, never from per-entry
timestamps.  Use what the server sends us to know whether or not there
are more updates to fetch.  Eliminate some unnecessarily complicated
logic having to do with the # of updates returned -- that's always a red
herring; with server-side filtering, it is indeed possible for 0 updates
to be returned along with a new timestamp.

BUG=37373
TEST=manual testing of 2 browser sync; unit tests.

Review URL: http://codereview.chromium.org/1161006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@42413 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/common/ipc_test_sink.h b/chrome/common/ipc_test_sink.h
index ec1e70c..973fc71 100644
--- a/chrome/common/ipc_test_sink.h
+++ b/chrome/common/ipc_test_sink.h
@@ -39,7 +39,7 @@
 //   test_sink.ClearMessages();
 //
 // To hook up the sink, all you need to do is call OnMessageReceived when a
-// message is recieved.
+// message is received.
 class TestSink {
  public:
   TestSink();