Changed the update protocol for component updater from v2 to v3.
BUG=314521

Review URL: https://codereview.chromium.org/74893002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236727 0039d316-1c4b-4281-b951-d872f2087c98
Fix a crash when prerendering a page with video

WebContents may not have a ContentViewCoreImpl in this case.
We need to check the pointer before using it.

BUG=321676

Review URL: https://codereview.chromium.org/79323004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236728 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236728