Revert 253010 "Revert 251563 "Move browser initiated navigation ..."

Looks like it wasn't responsible, and we've re-landed r249676 as well.

> Revert 251563 "Move browser initiated navigation from RenderView..."
> 
> Speculatively revert to help diagnose bug 345757.
> Mainly useful to make it easier to revert r249676, which changes the
> lifetime of RenderViewHosts.
> 
> > Move browser initiated navigation from RenderViewHost to RenderFrameHost.
> > 
> > BUG=304341
> > TBR=jochen@chromium.org
> > 
> > Review URL: https://codereview.chromium.org/148083013
> 
> TBR=nasko@chromium.org
> 
> Review URL: https://codereview.chromium.org/177713006

TBR=nasko@chromium.org, ajwong@chromium.org

Review URL: https://codereview.chromium.org/181113009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254174 0039d316-1c4b-4281-b951-d872f2087c98