Fix PathProvider to not modify result when DIR_TEST_DATA does not exist

base/base_paths.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/base_paths.h"
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/path_service.h"
 
@@ skipping 11 matching lines @@
       PathService::Get(FILE_MODULE, result);
       *result = result->DirName();
       return true;
     case DIR_TEMP:
       if (!GetTempDir(result))
         return false;
       return true;
     case base::DIR_HOME:
       *result = GetHomeDir();
       return true;
-    case DIR_TEST_DATA:
-      if (!PathService::Get(DIR_SOURCE_ROOT, result))
+    case DIR_TEST_DATA: {
+      FilePath test_data_path;
+      if (!PathService::Get(DIR_SOURCE_ROOT, &test_data_path))
         return false;
-      *result = result->Append(FILE_PATH_LITERAL("base"));
-      *result = result->Append(FILE_PATH_LITERAL("test"));
-      *result = result->Append(FILE_PATH_LITERAL("data"));
-      if (!PathExists(*result))  // We don't want to create this.
+      test_data_path = test_data_path.Append(FILE_PATH_LITERAL("base"));
+      test_data_path = test_data_path.Append(FILE_PATH_LITERAL("test"));
+      test_data_path = test_data_path.Append(FILE_PATH_LITERAL("data"));
+      if (!PathExists(test_data_path))  // We don't want to create this.
         return false;
+      *result = test_data_path;
       return true;
+    }
     default:
       return false;
   }
 }
 
 }  // namespace base