* 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
double level) {
  content::HostZoomMap::SetZoomLevel(web_contents, level);
}
double GetNextZoomLevel(double level, bool out) {
  double factor = content::ZoomLevelToZoomFactor(level);
  size_t size = arraysize(kPresetZoomFactors);
  for (size_t i = 0; i < size; ++i) {
    if (!content::ZoomValuesEqual(kPresetZoomFactors[i], factor))
      continue;
    if (out && i > 0)
      return content::ZoomFactorToZoomLevel(kPresetZoomFactors[i - 1]);
    if (!out && i != size - 1)
      return content::ZoomFactorToZoomLevel(kPresetZoomFactors[i + 1]);
  }
  return level;
}
GURL GetRemoteBaseURL() {
  return GURL(base::StringPrintf("%s%s/%s/",
                                 kChromeUIDevToolsRemoteFrontendBase,
                                 kChromeUIDevToolsRemoteFrontendPath,
                                 content::GetWebKitRevision().c_str()));
}
GURL GetDevToolsURL(bool can_dock) {
  auto url_string = base::StringPrintf(kChromeUIDevToolsURL,
                                       GetRemoteBaseURL().spec().c_str(),
                                       can_dock ? "true" : "");
  return GURL(url_string);
}
class ResponseWriter : public net::URLFetcherResponseWriter {