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
bool WebContentsImpl::NeedToFireBeforeUnload() {
  return WillNotifyDisconnection() &&
      !ShowingInterstitialPage() &&
      !static_cast<RenderViewHostImpl*>(
          GetRenderViewHost())->SuddenTerminationAllowed();
}

bool WebContentsImpl::NeedToFireBeforeUnload() {
  return WillNotifyDisconnection() &&
      !ShowingInterstitialPage() &&
      !static_cast<RenderViewHostImpl*>(
          GetRenderViewHost())->SuddenTerminationAllowed();
}
