Roll ffmpeg/libvpx deps to switch to ffvp8.

DEPS

 vars = {
   # Use this googlecode_url variable only if there is an internal mirror for it.
   # If you do not know, use the full path while defining your new deps entry.
   "googlecode_url": "http://%s.googlecode.com/svn",
   "webkit_trunk": "http://svn.webkit.org/repository/webkit/trunk",
   "nacl_trunk": "http://src.chromium.org/native_client/trunk",
   "webkit_revision": "93038",
   "chromium_git": "http://git.chromium.org/git",
   "swig_revision": "69281",
   # These hashes need to be updated when nacl_revision is changed.
   # After changing nacl_revision, run 'gclient runhooks' to get the new values.
   "nacl_irt_hash_x86_32": "05b19a95dbaa460ca72969268332aa678823ed01",
   "nacl_irt_hash_x86_64": "7ec40d9483348dbecff8c32aa7176cc734f0708d",
   "nacl_revision": "6416",
   # After changing nacl_revision, run 'glient sync' and check native_client/DEPS
   # to update other nacl_*_revision's.
   # TODO(brettw) We should use the "From" syntax to avoid hardcoding the
   # revisions here, but it makes checkdeps confused. We should fix checkdeps.
   "nacl_chrome_ppapi_revision": "96558", # native_client/DEPS: chrome_ppapi_rev 
   "nacl_tools_revision": "5360",  # native_client/DEPS: tools_rev
   "libjingle_revision": "77",
-  "libvpx_revision": "96377",
-  "ffmpeg_revision": "96828",
+
+  # TODO(scherkus): update after http://codereview.chromium.org/7659006/ lands.
+  "libvpx_revision": "96377",  # UPDATEME
+  "ffmpeg_revision": "96828",  # UPDATEME
+
   "sfntly_revision": "43",
   "skia_revision": "2116",
   "v8_revision": "8933",
   "webrtc_revision": "242",
 
   # Note: On most bots, clang is not checked out via DEPS but by
   # tools/clang/scripts/update.sh. The script reads this line here.
   "clang_revision": "137563",
 }
 
@@ skipping 371 matching lines @@
   {
     # This downloads binaries for Native Client's integrated runtime (IRT)
     # library, which is built as NaCl untrusted code.
     "pattern": ".",
     "action": ["python", "src/build/download_nacl_irt.py",
                "--nacl_revision", Var("nacl_revision"),
                "--file_hash", "x86_32", Var("nacl_irt_hash_x86_32"),
                "--file_hash", "x86_64", Var("nacl_irt_hash_x86_64")],
   },
 ]