Roll ffmpeg deps to include valgrind gyps fixes.

ffmpeg_rev:
http://src.chromium.org/viewvc/chrome?view=rev&revision=125083

ffmpeg_hash:
http://git.chromium.org/gitweb/?p=chromium/third_party/ffmpeg.git;a=commit;h=4e37a64923324198527aad38da497385deaf9184

BUG=109780
TEST=Built ffmpeg.

Review URL: http://codereview.chromium.org/9554015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@125127 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/DEPS b/DEPS
index 9c096b3..313efe7 100644
--- a/DEPS
+++ b/DEPS
@@ -46,8 +46,8 @@
 
   # These two FFmpeg variables must be updated together.  One is used for SVN
   # checkouts and the other for Git checkouts.
-  "ffmpeg_revision": "124825",
-  "ffmpeg_hash": "baa5f11e7dc682b2bb5545e9fbf037090b99fff1",
+  "ffmpeg_revision": "125083",
+  "ffmpeg_hash": "4e37a64923324198527aad38da497385deaf9184",
 
   "sfntly_revision": "128",
   "skia_revision": "3312",