If JavaScript shows a dialog, cause the page to lose fullscreen.

BUG=670135, 550017, 726761, 728276

Review-Url: https://codereview.chromium.org/2906133004
Cr-Commit-Position: refs/heads/master@{#478884}
void WebContentsImpl::DidChangeName(RenderFrameHost* render_frame_host,
                                    const std::string& name) {
  for (auto& observer : observers_)
    observer.FrameNameChanged(render_frame_host, name);
}

void WebContentsImpl::DidChangeName(RenderFrameHost* render_frame_host,
                                    const std::string& name) {
  for (auto& observer : observers_)
    observer.FrameNameChanged(render_frame_host, name);
}
