* 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
const std::string& content) {
  if (delegate_)
    delegate_->DevToolsAppendToFile(url, content);
}
void InspectableWebContentsImpl::RequestFileSystems() {
  if (delegate_)
    delegate_->DevToolsRequestFileSystems();
}
void InspectableWebContentsImpl::AddFileSystem(const std::string& type) {
  if (delegate_)
    delegate_->DevToolsAddFileSystem(type, base::FilePath());
}
void InspectableWebContentsImpl::RemoveFileSystem(
    const std::string& file_system_path) {
  if (delegate_)
    delegate_->DevToolsRemoveFileSystem(
        base::FilePath::FromUTF8Unsafe(file_system_path));
}
void InspectableWebContentsImpl::UpgradeDraggedFileSystemPermissions(
    const std::string& file_system_url) {}
void InspectableWebContentsImpl::IndexPath(
    int request_id,
    const std::string& file_system_path,
    const std::string& excluded_folders) {
  if (delegate_)
    delegate_->DevToolsIndexPath(request_id, file_system_path,
                                 excluded_folders);
}
void InspectableWebContentsImpl::StopIndexing(int request_id) {