Cleanup: Fix comments for IPC messages that got renamed.

Review URL: https://codereview.chromium.org/158303002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250231 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250231
Mojo: Small MessageInTransit fixes.

R=yzshen@chromium.org

Review URL: https://codereview.chromium.org/155953006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250232 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250232