Roll src/third_party/ffmpeg/ 5baad9325..dee930847 (1 commit)

https://chromium.googlesource.com/chromium/third_party/ffmpeg.git/+log/5baad932589a..dee930847568

$ git log 5baad9325..dee930847 --date=short --no-merges --format='%ad %ae %s'
2018-03-30 fdegans Prepare for |is_posix| switch in the Fuchsia build

Created with:
  roll-dep src/third_party/ffmpeg

Bug: 812974
Change-Id: I28381804667b9b6a2fd085545db6bf3c80cd3009
Reviewed-on: https://chromium-review.googlesource.com/996474Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548276}

DEPS

@@ -471,7 +471,7 @@ deps = {
   },
 
   'src/third_party/ffmpeg':
-    Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + '5baad932589a94969782df630db02ec0293d920f',
+    Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + 'dee930847568b85e25ef6db3e87a563057731e32',
 
   'src/third_party/flac':
     Var('chromium_git') + '/chromium/deps/flac.git' + '@' + '7d0f5b3a173ffe98db08057d1f52b7787569e0a6',