Add wxBitmapBundle::IsSameAs()

This is useful if only for compatibility with wxBitmap or wxIcon, that
have the same member function with the same semantics.

include/wx/bmpbndl.h

@@ -123,6 +123,11 @@ public:
     // Access implementation
     wxBitmapBundleImpl* GetImpl() const { return m_impl.get(); }
 
+    // Check if two objects refer to the same bundle.
+    bool IsSameAs(const wxBitmapBundle& other) const
+    {
+        return GetImpl() == other.GetImpl();
+    }
 
     // Implementation only from now on.
 

interface/wx/bmpbndl.h

@@ -341,6 +341,16 @@ public:
         the returned bitmap to wxIcon.
      */
     wxIcon GetIcon(const wxSize& size) const;
+
+    /**
+        Check if the two bundles refer to the same object.
+
+        Bundles are considered to be same only if they actually use the same
+        underlying object, i.e. are copies of each other. If the two bundles
+        were independently constructed, they're @e not considered to be the
+        same, even if they were created from the same bitmap.
+     */
+    bool IsSameAs(const wxBitmapBundle& other) const;
 };
 
 /**