* Output of `node_modules/.bin/electron --version`: 2.0.0
* Operating System (Platform and Version): Windows 10

**Expected Behavior**
When I disable a window twice via `setEnabled(false)`, I expect the second disable to have no effect.

**Actual behavior**
The second disable is "queued" up, such that I am forced to enable the window twice to get back to normal.

**To Reproduce**
In the electronquickstart repo, in main.js' `createWindow()`, add these lines:

    mainWindow.setEnabled(false);
    mainWindow.setEnabled(false);
    mainWindow.setEnabled(true);

The window will be disabled when launched. 

You see the same issue if you do it in reverse:

    mainWindow.setEnabled(true);
    mainWindow.setEnabled(false); // this doesn't actually disable it, because the window was enabled from the getgo

If this is expected behavior, can the [docs](https://github.com/electron/electron/blob/master/docs/api/browser-window.md#winsetenabledenable) be updated to explain this behavior.
atom/browser/native_window_views.cc
return content_view() ? content_view()->GetBoundsInScreen() : gfx::Rect();
}
gfx::Size NativeWindowViews::GetContentSize() {
#if defined(OS_WIN)
  if (IsMinimized())
    return NativeWindow::GetContentSize();
#endif
  return content_view() ? content_view()->size() : gfx::Size();
}
gfx::Rect NativeWindowViews::GetNormalBounds() {
  return widget()->GetRestoredBounds();
}
void NativeWindowViews::SetContentSizeConstraints(
    const extensions::SizeConstraints& size_constraints) {
  NativeWindow::SetContentSizeConstraints(size_constraints);
#if defined(OS_WIN)
  
  
  if (!thick_frame_)
    return;
#endif
  
  
  if (widget() && widget()->widget_delegate())
    widget()->OnSizeConstraintsChanged();
  if (resizable_)
    old_size_constraints_ = size_constraints;
}
void NativeWindowViews::SetResizable(bool resizable) {