Remove wxWebResponse::AsString() conversion parameter

It doesn't make much sense to specify the conversion here, it would
ideally be taken from the response Content-Type header itself and
currently is just assumed to be UTF-8 anyhow.

Also implement fallback to Latin-1 to avoid losing the data entirely if
it's not in UTF-8.

include/wx/webrequest.h

@@ -152,7 +152,7 @@ public:
 
     virtual wxString GetSuggestedFileName() const;
 
-    wxString AsString(wxMBConv* conv = NULL) const;
+    wxString AsString() const;
 
     bool Init();
 

interface/wx/webrequest.h

@@ -450,11 +450,9 @@ public:
     /**
         Returns all response data as a string.
 
-        @param conv wxMBConv used to convert the response to a string.
+        This is mostly useful for debugging or diagnostics.
-                    If @c NULL, the conversion will be determined by
-                    response headers. The default is UTF-8.
     */
-    wxString AsString(wxMBConv* conv = NULL) const;
+    wxString AsString() const;
 };
 
 /**

src/common/webrequest.cpp

@@ -345,16 +345,13 @@ wxString wxWebResponse::GetSuggestedFileName() const
     return suggestedFilename;
 }
 
-wxString wxWebResponse::AsString(wxMBConv * conv) const
+wxString wxWebResponse::AsString() const
 {
-    // TODO: try to determine encoding type from content-type header
-    if ( !conv )
-        conv = &wxConvUTF8;
-
     if ( m_request.GetStorage() == wxWebRequest::Storage_Memory )
     {
+        // TODO: try to determine encoding type from content-type header
         size_t outLen = 0;
-        return conv->cMB2WC((const char*)m_readBuffer.GetData(), m_readBuffer.GetDataLen(), &outLen);
+        return wxConvWhateverWorks.cMB2WC((const char*)m_readBuffer.GetData(), m_readBuffer.GetDataLen(), &outLen);
     }
     else
         return wxString();