* 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
dict->SetInteger("x", bounds.x());
  dict->SetInteger("y", bounds.y());
  dict->SetInteger("width", bounds.width());
  dict->SetInteger("height", bounds.height());
}
void DictionaryToRect(const base::DictionaryValue& dict, gfx::Rect* bounds) {
  int x = 0, y = 0, width = 800, height = 600;
  dict.GetInteger("x", &x);
  dict.GetInteger("y", &y);
  dict.GetInteger("width", &width);
  dict.GetInteger("height", &height);
  *bounds = gfx::Rect(x, y, width, height);
}
bool IsPointInRect(const gfx::Point& point, const gfx::Rect& rect) {
  return point.x() > rect.x() && point.x() < (rect.width() + rect.x()) &&
         point.y() > rect.y() && point.y() < (rect.height() + rect.y());
}
bool IsPointInScreen(const gfx::Point& point) {
  for (const auto& display : display::Screen::GetScreen()->GetAllDisplays()) {
    if (IsPointInRect(point, display.bounds()))
      return true;
  }
  return false;
}
void SetZoomLevelForWebContents(content::WebContents* web_contents,