LibGfx: Add Size::contains

Author: https://github.com/tomuta
Commit: https://github.com/SerenityOS/serenity/commit/a2bffc850a3
Pull-request: https://github.com/SerenityOS/serenity/pull/3751

Libraries/LibGfx/Size.h

@@ -68,6 +68,12 @@ public:
     void set_width(T w) { m_width = w; }
     void set_height(T h) { m_height = h; }
 
+    template<typename U>
+    bool contains(const Size<U>& other) const
+    {
+        return other.m_width <= m_width && other.m_height <= m_height;
+    }
+
     bool operator==(const Size<T>& other) const
     {
         return m_width == other.m_width && m_height == other.m_height;