* Output of `node_modules/.bin/electron --version`: v3.0.0-beta.8
* Operating System (Platform and Version): Windows 10 10.0.16299 Build 16299
* Output of `node_modules/.bin/electron --version` on last known working Electron version (if applicable): v2.0.8

**Expected Behavior**
Webview DevTools should open in a window that is properly sized.

**Actual behavior**
Webview DevTools open in window with minimal size and are therefore not visible.

**To Reproduce**
**Edit** Works in BrowserWindow.webContents.openDevTools() Works **not** in webView.openDevTools()

**Screenshots**
![too_small_devtools_window](https://user-images.githubusercontent.com/6893212/44841398-850fed80-ac43-11e8-8bed-849d45473683.png)

**Additional Information**
Only reproducible on Windows 10 10.0.16299 Build 16299. Works correctly on MacOS High Sierra 10.13.4

brightray/browser/inspectable_web_contents_impl.cc
void InspectableWebContentsImpl::InspectedURLChanged(const std::string& url) {
  if (managed_devtools_web_contents_)
    view_->SetTitle(
        base::UTF8ToUTF16(base::StringPrintf(kTitleFormat, url.c_str())));
}
void InspectableWebContentsImpl::LoadNetworkResource(
    const DispatchCallback& callback,
    const std::string& url,
    const std::string& headers,
    int stream_id) {
  GURL gurl(url);
  if (!gurl.is_valid()) {
    base::DictionaryValue response;
    response.SetInteger("statusCode", 404);
    callback.Run(&response);
    return;
  }
  auto* browser_context = static_cast<BrowserContext*>(
      GetDevToolsWebContents()->GetBrowserContext());
  net::URLFetcher* fetcher =
      (net::URLFetcher::Create(gurl, net::URLFetcher::GET, this)).release();
  pending_requests_[fetcher] = callback;
  fetcher->SetRequestContext(browser_context->GetRequestContext());
  fetcher->SetExtraRequestHeaders(headers);
  fetcher->SaveResponseWithWriter(
      std::unique_ptr<net::URLFetcherResponseWriter>(
          new ResponseWriter(weak_factory_.GetWeakPtr(), stream_id)));
  fetcher->Start();
}
void InspectableWebContentsImpl::SetIsDocked(const DispatchCallback& callback,