Added check for negative height/width and ensure that buffer size has not changed before reading buffers.

Patch by cdn@chromium.org:
http://codereview.chromium.org/2479002/show

BUG=43322
TEST=Run with --enable-video-layering and --enable-gpu-rendering and use <video> tag

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@49132 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed