Convert RFH pointers to scoped_ptr inside RFHM.

BUG=

Review URL: https://codereview.chromium.org/191703002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256146 0039d316-1c4b-4281-b951-d872f2087c98
Enable mojo unittests on chromium_trybot and waterfall bots.

BUG=346766
TEST=the tests should succeed, including on Mac.
R=phajdan.jr@chromium.org, viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/189583009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256147 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256146
SVN changes up to revision 256147
Remove platform ifdef in testing code that's no longer needed

BUG=none

Review URL: https://codereview.chromium.org/187083005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256148 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256148