Make wxPalette ctor and Create() const-correct in wxMSW.

The input data is never modified so should be const (it is also documented as
being const and actually is const in the other ports).

Closes #13776.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70040 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/palette.h

@@ -19,13 +19,13 @@ class WXDLLIMPEXP_CORE wxPalette : public wxPaletteBase
 public:
     wxPalette() { }
     wxPalette(int n,
-              unsigned char *red, unsigned char *green, unsigned char *blue)
+              const unsigned char *red, const unsigned char *green, const unsigned char *blue)
     {
         Create(n, red, green, blue);
     }
 
     bool Create(int n,
-                unsigned char *red, unsigned char *green, unsigned char *blue);
+                const unsigned char *red, const unsigned char *green, const unsigned char *blue);
 
     virtual int GetColoursCount() const;
 

src/msw/palette.cpp

@@ -32,9 +32,9 @@ public:
     wxPaletteRefData() { Init(); }
 
     wxPaletteRefData(int n,
-                     unsigned char *red,
+                     const unsigned char *red,
-                     unsigned char *green,
+                     const unsigned char *green,
-                     unsigned char *blue)
+                     const unsigned char *blue)
     {
         Init();
 
@@ -117,9 +117,9 @@ IMPLEMENT_DYNAMIC_CLASS(wxPalette, wxGDIObject)
 #define M_PALETTEDATA ((wxPaletteRefData *)m_refData)
 
 bool wxPalette::Create(int n,
-                       unsigned char *red,
+                       const unsigned char *red,
-                       unsigned char *green,
+                       const unsigned char *green,
-                       unsigned char *blue)
+                       const unsigned char *blue)
 {
     m_refData = new wxPaletteRefData(n, red, green, blue);