Fixes bug where MessagePumpMojo was listening for state on the wrong handle

Test will be forth coming, but wanted to land this now.

BUG=none
TEST=none
R=viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/68523010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234973 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234973