Roll src/third_party/ffmpeg/ 75cc116fa..be66dc5fd (2 commits)

https://chromium.googlesource.com/chromium/third_party/ffmpeg.git/+log/75cc116fa06d..be66dc5fd0e3

$ git log 75cc116fa..be66dc5fd --date=short --no-merges --format='%ad %ae %s'
2020-05-18 dalecurtis Update patches for memory leak fix.
2020-05-18 dalecurtis Free temp buffer upon negative sample_size error.

Created with:
  roll-dep src/third_party/ffmpeg

TBR=sandersd

Fixed: 1083880
Change-Id: I678a50bf0b0f842ea25bb72ced5cc8c5b636f63d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2208093Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#769922}

DEPS

@@ -896,7 +896,7 @@ deps = {
   },
 
   'src/third_party/ffmpeg':
-    Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + '75cc116fa06d7f7ec29c9cb655332deed39d8300',
+    Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + 'be66dc5fd0e3c53646107b2dc5d7594a869ebdc6',
 
   'src/third_party/flac':
     Var('chromium_git') + '/chromium/deps/flac.git' + '@' + 'af862024c8c8fa0ae07ced05e89013d881b00596',