Roll deps for ffmpeg security fixes and add new test case.

media/ffmpeg/ffmpeg_regression_tests.cc

Index: media/ffmpeg/ffmpeg_regression_tests.cc
diff --git a/media/ffmpeg/ffmpeg_regression_tests.cc b/media/ffmpeg/ffmpeg_regression_tests.cc
index 294fd22034e6ed07425b9f9d10c5743c73dbbc96..a145bdde77768dc69b7f37267fb2321e0c2b0f85 100644
--- a/media/ffmpeg/ffmpeg_regression_tests.cc
+++ b/media/ffmpeg/ffmpeg_regression_tests.cc
@@ -136,6 +136,8 @@ FFMPEG_TEST_CASE(WEBM_4, "security/out.webm.68798.1929",
                  DECODER_ERROR_NOT_SUPPORTED, DECODER_ERROR_NOT_SUPPORTED);
 FFMPEG_TEST_CASE(WEBM_5, "content/frame_size_change.webm", PIPELINE_OK,
                  PIPELINE_OK);
+FFMPEG_TEST_CASE(WEBM_6, "security/117912.webm", DEMUXER_ERROR_COULD_NOT_OPEN,
+                 DEMUXER_ERROR_COULD_NOT_OPEN);
 
 // Flaky, maybe larger issues.  All eventually fail in the browser.
 FFMPEG_TEST_CASE(FLAKY_Cr99652, "security/99652.webm", PIPELINE_OK,