We need to pass "muted" as a web page creation parameter, and make sure HTMLMediaElement respects the page's current muted state during initialization.
Created attachment 240706 [details] Patch
The second part of the bug about making sure HTMLMediaElement respecting the page's current muted state during initialization has been fixed as part of https://bugs.webkit.org/show_bug.cgi?id=138215.
Committed: http://trac.webkit.org/changeset/175473