* 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
content::RenderWidgetHost* render_widget_host) {
#if defined(TOOLKIT_VIEWS)
  if (view_->GetDelegate())
    view_->GetDelegate()->DevToolsFocused();
#endif
}
void InspectableWebContentsImpl::ReadyToCommitNavigation(
    content::NavigationHandle* navigation_handle) {
  if (navigation_handle->IsInMainFrame()) {
    if (navigation_handle->GetRenderFrameHost() ==
            GetDevToolsWebContents()->GetMainFrame() &&
        frontend_host_) {
      return;
    }
    frontend_host_.reset(content::DevToolsFrontendHost::Create(
        web_contents()->GetMainFrame(),
        base::Bind(
            &InspectableWebContentsImpl::HandleMessageFromDevToolsFrontend,
            base::Unretained(this))));
    return;
  }
}
void InspectableWebContentsImpl::DidFinishNavigation(