GitLab

This is mostly the Interceptor logic which is now unused.
Also switch DebugDevToolsInterceptor (the last remaining
Interceptor) to a ProtocolHandler.

BUG=146602,161529

Review URL: https://chromiumcodereview.appspot.com/12217095

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182016 0039d316-1c4b-4281-b951-d872f2087c98