Revert 252624 "Add disable WebRTC encryption tests."

> Add disable WebRTC encryption tests.
> 
> - Broke out copying of the disable encryption command line flag to its own function. Added unit test for it.
> - Added browser test.
> 
> BUG=342294
> 
> Review URL: https://codereview.chromium.org/170623003

BUG=345813
TBR=grunell@chromium.org

Review URL: https://codereview.chromium.org/175793003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252648 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252648