Revert 249293 "Revert 248828 "<webview>: navigating to WebStore ..."

> Revert 248828 "<webview>: navigating to WebStore should fire a l..."
> 
> > <webview>: navigating to WebStore should fire a loadabort instead of crashing.
> > 
> > All top-level navigations now get plumbed through: BrowserPluginGuest::LoadURLWithParams.
> > URL validation now happens there. If a URL is determined to be inappropriate for a <webview>,
> > a loadabort event will fire instead of crashing the <webview> guest content.
> > 
> > BUG=334531
> > Test=WebViewTest.Shim_TestNavigateToWebStore
> > 
> > Review URL: https://codereview.chromium.org/140073002
> 
> TBR=fsamuel@chromium.org
> 
> Review URL: https://codereview.chromium.org/152783004

TBR=hajimehoshi@chromium.org

Review URL: https://codereview.chromium.org/151243004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249482 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249482