Docserver: Use GitilesFileSystem instead of SubversionFileSystem

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

Index: chrome/common/extensions/docs/server2/mock_file_system.py
diff --git a/chrome/common/extensions/docs/server2/mock_file_system.py b/chrome/common/extensions/docs/server2/mock_file_system.py
index 52a84bde7b4b54e6c88a03c39d0593dcd1d4ab56..76942f809da1f83599927a8383dcae6096bc4795 100644
--- a/chrome/common/extensions/docs/server2/mock_file_system.py
+++ b/chrome/common/extensions/docs/server2/mock_file_system.py
@@ -85,6 +85,12 @@ class MockFileSystem(FileSystem):
 
     return stat
 
+  def GetCommitID(self):
+    return Future(value=self._stat_tracker.GetVersion(''))
+
+  def GetPreviousCommitID(self):
+    return Future(value=self._stat_tracker.GetVersion('') - 1)
+
   def GetIdentity(self):
     return self._file_system.GetIdentity()