Add support for returning item location to wxGTK wxMimeTypesManager.

This is a squash merge of gtk_mimetype branch from
https://github.com/Hanmac/wxWidgets.git with some extra minor cleanup.

Closes https://github.com/wxWidgets/wxWidgets/pull/293

src/gtk/app.cpp

@@ -31,6 +31,7 @@
 #include <gtk/gtk.h>
 #include "wx/gtk/private.h"
 
+#include "wx/gtk/mimetype.h"
 //-----------------------------------------------------------------------------
 // link GnomeVFS
 //-----------------------------------------------------------------------------
@@ -435,6 +436,10 @@ bool wxApp::Initialize(int& argc_, wxChar **argv_)
         return false;
     }
 
+#if wxUSE_MIMETYPE
+    wxMimeTypesManagerFactory::Set(new wxGTKMimeTypesManagerFactory());
+#endif
+
     // we cannot enter threads before gtk_init is done
     gdk_threads_enter();
 

src/gtk/mimetype.cpp

@@ -0,0 +1,52 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        src/gtk/mimetype.cpp
+// Purpose:     classes and functions to manage MIME types
+// Author:      Hans Mackowiak
+// Created:     2016-06-05
+// Copyright:   (c) 2016 Hans Mackowiak <hanmac@gmx.de>
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#include "wx/wxprec.h"
+
+#if wxUSE_MIMETYPE
+
+#include "wx/gtk/mimetype.h"
+
+#include <gio/gio.h>
+#include <gtk/gtk.h>
+
+#include "wx/gtk/private/string.h"
+#include "wx/gtk/private/object.h"
+
+wxString wxGTKMimeTypesManagerImpl::GetIconFromMimeType(const wxString& mime)
+{
+    wxGtkString type(g_content_type_from_mime_type(mime.utf8_str()));
+
+    wxGtkObject<GIcon> gicon(g_content_type_get_icon(type));
+    if ( !gicon )
+        return wxString();
+
+    GtkIconTheme *theme(gtk_icon_theme_get_default());
+    if ( !theme )
+        return wxString();
+
+    wxGtkObject<GtkIconInfo> giconinfo(gtk_icon_theme_lookup_by_gicon
+                                       (
+                                            theme,
+                                            gicon,
+                                            256,
+                                            GTK_ICON_LOOKUP_NO_SVG
+                                       ));
+    if ( !giconinfo )
+        return wxString();
+
+    return wxString::FromUTF8(gtk_icon_info_get_filename(giconinfo));
+}
+
+wxMimeTypesManagerImpl *wxGTKMimeTypesManagerFactory::CreateMimeTypesManagerImpl()
+{
+    return new wxGTKMimeTypesManagerImpl();
+}
+
+#endif // wxUSE_MIMETYPE

src/unix/mimetype.cpp

@@ -262,7 +262,9 @@ void wxMimeTypesManagerImpl::LoadXDGGlobs(const wxString& filename)
        wxArrayString exts;
        exts.Add( ext );
 
-       AddToMimeData(mime, wxEmptyString, NULL, exts, wxEmptyString, true );
+       wxString icon = GetIconFromMimeType(mime);
+
+       AddToMimeData(mime, icon, NULL, exts, wxEmptyString, true );
     }
 }
 
@@ -687,6 +689,11 @@ wxFileType * wxMimeTypesManagerImpl::Associate(const wxFileTypeInfo& ftInfo)
     return GetFileTypeFromMimeType(strType);
 }
 
+wxString wxMimeTypesManagerImpl::GetIconFromMimeType(const wxString& WXUNUSED(mime))
+{
+    return wxString();
+}
+
 bool wxMimeTypesManagerImpl::DoAssociation(const wxString& strType,
                                            const wxString& strIcon,
                                            wxMimeTypeCommands *entry,
@@ -967,7 +974,7 @@ void wxMimeTypesManagerImpl::AddMimeTypeInfo(const wxString& strMimeType,
     // reading mailcap may find image/* , while
     // reading mime.types finds image/gif and no match is made
     // this means all the get functions don't work  fix this
-    wxString strIcon;
+    const wxString strIcon = GetIconFromMimeType(strMimeType);
     wxString sTmp = strExtensions;
 
     wxArrayString sExts;