move SK_MMAP_SUPPORT into SkPreConfig, so we can know about its availability

trunk/src/ports/SkFontHost_freetype_mac.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkFontHost.h"
-#include "SkMMapStream.h"
 #include "SkTypefaceCache.h"
 
 #define FONT_PATH   "/Library/Fonts/Skia.ttf"
 
 class FTMacTypeface : public SkTypeface {
 public:
     FTMacTypeface(Style style, uint32_t id, SkStream* stream) : SkTypeface(style, id) {
         // we take ownership of the stream
         fStream = stream;
     }
 
     virtual ~FTMacTypeface() {
         fStream->unref();
     }
 
     SkStream* fStream;
 };
 
 static FTMacTypeface* create_from_path(const char path[]) {
-    SkStream* stream = new SkMMAPStream(path);
+    SkStream* stream = SkStream::NewFromFile(path);
+    if (!stream) {
+        return NULL;
+    }
+
     size_t size = stream->getLength();
     SkASSERT(size);
     FTMacTypeface* tf = new FTMacTypeface(SkTypeface::kNormal,
                                           SkTypefaceCache::NewFontID(),
                                           stream);
     SkTypefaceCache::Add(tf, SkTypeface::kNormal);
     return tf;
 }
 
 static SkTypeface* ref_default_typeface() {
@@ skipping 56 matching lines @@
 SkFontID SkFontHost::NextLogicalFont(SkFontID currFontID, SkFontID origFontID) {
     return 0;
 }
 
 #include "SkTypeface_mac.h"
 
 SkTypeface* SkCreateTypefaceFromCTFont(CTFontRef fontRef) {
     SkDEBUGFAIL("Not supported");
     return NULL;
 }