Revert 253869 "Mojo: Add hooks for dispatchers to serialize them..."

> Mojo: Add hooks for dispatchers to serialize themselves.
> 
> R=yzshen@chromium.org
> 
> Review URL: https://codereview.chromium.org/182163002

TBR=viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/183173004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253876 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253876