Add ffmpeg (chromium's branch) to third_party for use in mojo media.

DEPS

 # This file is automatically processed to create .DEPS.git which is the file
 # that gclient uses under git.
 #
 # See http://code.google.com/p/chromium/wiki/UsingGit
 #
 # To test manually, run:
 #   python tools/deps2git/deps2git.py -o .DEPS.git -w <gclientdir>
 # where <gcliendir> is the absolute path to the directory containing the
 # .gclient file (the parent of 'src').
 #
@@ skipping 102 matching lines @@
     Var('chromium_git') + '/external/google-breakpad/src.git' + '@' + '242fb9a38db6ba534b1f7daa341dd4d79171658b', # from svn revision 1471
 
   'src/third_party/lss':
     Var('chromium_git') + '/external/linux-syscall-support/lss.git' + '@' + Var('lss_revision'),
 
   'src/third_party/leveldatabase/src':
     Var('chromium_git') + '/external/leveldb.git' + '@' + '40c17c0b84ac0b791fb434096fd5c05f3819ad55',
 
   'src/third_party/snappy/src':
     Var('chromium_git') + '/external/snappy.git' + '@' + '762bb32f0c9d2f31ba4958c7c0933d22e80c20bf',
+
+  'src/third_party/ffmpeg':
+     Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + '525a71ab8ee3b61da48138f7e1c406989d2879fc',
 }
 
 deps_os = {
   'android': {
     'src/third_party/colorama/src':
      Var('chromium_git') + '/external/colorama.git' + '@' + '799604a1041e9b3bc5d2789ecbd7e8db2e18e6b8',
 
     'src/third_party/jsr-305/src':
         Var('chromium_git') + '/external/jsr-305.git' + '@' + '642c508235471f7220af6d5df2d3210e3bfc0919',
 
@@ skipping 254 matching lines @@
     'pattern': '',
     'action': [ 'download_from_google_storage',
                 '--no_resume',
                 '--quiet',
                 '--no_auth',
                 '--bucket', 'mojo/prediction',
                 '-d', 'src/services/prediction/res',
     ],
   },
 ]