Add path utils, plus a test for it.

gm/gmmain.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.
  */
 
 /*
  * Code for the "gm" (Golden Master) rendering comparison tool.
  *
@@ skipping 204 matching lines @@
      */
     SkString make_filename(const char *path,
                            const char *shortName,
                            const char *configName,
                            const char *renderModeDescriptor,
                            const char *suffix) {
         SkString filename = make_shortname_plus_config(shortName, configName);
         filename.append(renderModeDescriptor);
         filename.appendUnichar('.');
         filename.append(suffix);
-        return SkPathJoin(path, filename.c_str());
+        return SkOSPath::SkPathJoin(path, filename.c_str());
     }
 
     /* since PNG insists on unpremultiplying our alpha, we take no
        precision chances and force all pixels to be 100% opaque,
        otherwise on compare we may not get a perfect match.
     */
     static void force_all_opaque(const SkBitmap& bitmap) {
         SkBitmap::Config config = bitmap.config();
         switch (config) {
         case SkBitmap::kARGB_8888_Config:
@@ skipping 1842 matching lines @@
     if (FLAGS_forceBWtext) {
         canvas->setDrawFilter(SkNEW(BWTextDrawFilter))->unref();
     }
 }
 
 #if !defined(SK_BUILD_FOR_IOS) && !defined(SK_BUILD_FOR_NACL)
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif