Cancel JavaScript dialogs when an interstitial appears.

BUG=295695
TEST=See bug for repro steps.

Review URL: https://chromiumcodereview.appspot.com/24360011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225026 0039d316-1c4b-4281-b951-d872f2087c98
void WebContentsImpl::ViewFrameSource(const GURL& url,
                                      const PageState& page_state) {
  if (!delegate_)
    return;

  delegate_->ViewSourceForFrame(this, url, page_state);
}

void WebContentsImpl::ViewFrameSource(const GURL& url,
                                      const PageState& page_state) {
  if (!delegate_)
    return;

  delegate_->ViewSourceForFrame(this, url, page_state);
}
