Add wxBitmap::NewFromPNGData() for creating bitmaps from PNG data.

This simple function can be used to create a wxBitmap from the raw image data
in PNG format. It is just a thin wrapper around wxImage load functions under
almost all platforms but has two advantages:

1. It can be implemented natively for some platforms (currently only OS X).
2. It can be used in a single expression as it doesn't require creating a
   temporary wxMemoryInputStream and this will be required by wxBITMAP_PNG()
   macro that will be added soon.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72476 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/bitmap.h

@@ -584,6 +584,31 @@ public:
     */
     virtual bool LoadFile(const wxString& name, wxBitmapType type = wxBITMAP_DEFAULT_TYPE);
 
+    /**
+        Loads a bitmap from the memory containing image data in PNG format.
+
+        This helper function provides the simplest way to create a wxBitmap
+        from PNG image data. On most platforms, it's simply a wrapper around
+        wxImage loading functions and so requires the PNG image handler to be
+        registered by either calling wxInitAllImageHandlers() which also
+        registers all the other image formats or including the necessary
+        header:
+        @code
+            #include <wx/imagpng.h>
+        @endcode
+        and calling
+        @code
+            wxImage::AddHandler(new wxPNGHandler);
+        @endcode
+        in your application startup code.
+
+        However under OS X this function uses native image loading and so
+        doesn't require wxWidgets PNG support.
+
+        @since 2.9.5
+     */
+    static wxBitmap NewFromPNGData(const void* data, size_t size);
+
     /**
         Finds the handler with the given name, and removes it.
         The handler is not deleted.