* 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
CloseDevTools();
}
content::ColorChooser* InspectableWebContentsImpl::OpenColorChooser(
    content::WebContents* source,
    SkColor color,
    const std::vector<blink::mojom::ColorSuggestionPtr>& suggestions) {
  auto* delegate = web_contents_->GetDelegate();
  if (delegate)
    return delegate->OpenColorChooser(source, color, suggestions);
  return nullptr;
}
void InspectableWebContentsImpl::RunFileChooser(
    content::RenderFrameHost* render_frame_host,
    const content::FileChooserParams& params) {
  auto* delegate = web_contents_->GetDelegate();
  if (delegate)
    delegate->RunFileChooser(render_frame_host, params);
}
void InspectableWebContentsImpl::EnumerateDirectory(
    content::WebContents* source,
    int request_id,
    const base::FilePath& path) {
  auto* delegate = web_contents_->GetDelegate();
  if (delegate)
    delegate->EnumerateDirectory(source, request_id, path);
}
void InspectableWebContentsImpl::OnWebContentsFocused(