Revert 235494 "Create and configure CastSender from chrome exten..."

Speculative revert to find out the cause of Mac size regression.
Will follow up with more details or revert this revert.

> Create and configure CastSender from chrome extensions API
> 
> Implement default codec parameters and translate CastRtpCaps to
> AudioSenderConfig and VideoSenderConfig. This allows CastSender to be
> be created with default parameters.
> 
> Adding an extensions test that exercise these code.
> 
> BUG=301920
> 
> Review URL: https://codereview.chromium.org/60733021

TBR=hclam@chromium.org

Review URL: https://codereview.chromium.org/74943004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235622 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235622