Explicitly initialize media_format to avoid incorrect uninitialized-variable compiler warning.
Explicitly initialize media_format to avoid incorrect uninitialized-variable compiler warning.

TBR=acolwell

git-svn-id: http://src.chromium.org/svn/trunk/src@79752 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: ffda714893d154c97a5ce1dd8cb3c6c7d8fe3172
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser