Roll src/third_party/ffmpeg/ 48b037ba0..a1f3db690 (1 commit)

https://chromium.googlesource.com/chromium/third_party/ffmpeg.git/+log/48b037ba0de5..a1f3db690c65

$ git log 48b037ba0..a1f3db690 --date=short --no-merges --format='%ad %ae %s'
2020-08-26 xhwang Initialize `layout_map` on declaration

Created with:
  roll-dep src/third_party/ffmpeg

Tbr: dalecurtis@chromium.org
Bug: 1119532,1119331
Change-Id: I528650fc59aea9d3a7bfd8ca16d3be225e1e0ae7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2378872Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#802044}

DEPS

@@ -916,7 +916,7 @@ deps = {
   },
 
   'src/third_party/ffmpeg':
-    Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + '48b037ba0de5eecc97baf6e1d0133c4cc58485b1',
+    Var('chromium_git') + '/chromium/third_party/ffmpeg.git' + '@' + 'a1f3db690c654bc3c74381c61d4071c578e5f398',
 
   'src/third_party/flac':
     Var('chromium_git') + '/chromium/deps/flac.git' + '@' + 'af862024c8c8fa0ae07ced05e89013d881b00596',