Cleaning window managers for consistency.

src/windows/managers/WindowManager.h

@@ -27,6 +27,18 @@ public:
 
     void OnKeyboardEvent(const KeyboardEvent* event);
 
+    void clearPlatformWindows();
+
+    std::size_t getNumWindows() const
+    {
+        return mWindows.size();
+    }
+
+    mt::Window* getWindow(std::size_t idx) const
+    {
+        return mWindows[idx].get();
+    }
+
 private:
     std::vector<WindowUPtr> mWindows;
 };