* 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
bool discover_usb_devices,
    bool port_forwarding_enabled,
    const std::string& port_forwarding_config,
    bool network_discovery_enabled,
    const std::string& network_discovery_config) {}
void InspectableWebContentsImpl::SetDevicesUpdatesEnabled(bool enabled) {}
void InspectableWebContentsImpl::PerformActionOnRemotePage(
    const std::string& page_id,
    const std::string& action) {}
void InspectableWebContentsImpl::OpenRemotePage(const std::string& browser_id,
                                                const std::string& url) {}
void InspectableWebContentsImpl::OpenNodeFrontend() {}
void InspectableWebContentsImpl::DispatchProtocolMessageFromDevToolsFrontend(
    const std::string& message) {
  
  
  if (base::MatchPattern(message,
                         "{\"id\":*,"
                         "\"method\":\"Page.reload\","
                         "\"params\":*}")) {
    if (delegate_)
      delegate_->DevToolsReloadPage();
    return;
  }
  if (agent_host_)
    agent_host_->DispatchProtocolMessage(this, message);
}
void InspectableWebContentsImpl::SendJsonRequest(