Be able to build cast_unittest and related targets in Chrome tree

Adding cast.gyp to build/all.gyp. Also a bunch of chromium style errors.

Review URL: https://codereview.chromium.org/24586003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226264 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226264