Move browser initiated navigation from RenderViewHost to RenderFrameHost.

BUG=304341
TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/148083013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251563 0039d316-1c4b-4281-b951-d872f2087c98