Fix invalid reads detected by Valgrind when the frame size changes.

BUG=102789
Review URL: http://codereview.chromium.org/8497048

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/ffmpeg/source@109319 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
2 files changed