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
WebContents* WebContentsImpl::OpenURL(const OpenURLParams& params) {
  if (!delegate_)
    return NULL;

  WebContents* new_contents = delegate_->OpenURLFromTab(this, params);
  return new_contents;
}

WebContents* WebContentsImpl::OpenURL(const OpenURLParams& params) {
  if (!delegate_)
    return NULL;

  WebContents* new_contents = delegate_->OpenURLFromTab(this, params);
  return new_contents;
}
