Docserver: Use GitilesFileSystem instead of SubversionFileSystem

chrome/common/extensions/docs/server2/fake_host_file_system_provider.py

 # Copyright 2013 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.
 
 from mock_file_system import MockFileSystem
 from test_file_system import TestFileSystem
 from third_party.json_schema_compiler.memoize import memoize
 
 class FakeHostFileSystemProvider(object):
 
   def __init__(self, file_system_data):
     self._file_system_data = file_system_data
 
-  def GetTrunk(self):
-    return self.GetBranch('trunk')
+  def GetMaster(self):
+    return self.GetBranch('master')
 
   @memoize
   def GetBranch(self, branch):
     return MockFileSystem(TestFileSystem(self._file_system_data[str(branch)]))