Docserver: Use GitilesFileSystem instead of SubversionFileSystem

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

Index: chrome/common/extensions/docs/server2/gitiles_file_system.py
diff --git a/chrome/common/extensions/docs/server2/gitiles_file_system.py b/chrome/common/extensions/docs/server2/gitiles_file_system.py
index 5e2f86784a1b60dee722ef499514f234a2c92121..e903109a282893b0d14379b2be91fa21b756d8d6 100644
--- a/chrome/common/extensions/docs/server2/gitiles_file_system.py
+++ b/chrome/common/extensions/docs/server2/gitiles_file_system.py
@@ -106,7 +106,8 @@ class GitilesFileSystem(FileSystem):
     #       ...
     #   }
     def list_dir(json_data):
-      return [e['name'] for e in _ParseGitilesJson(json_data)['entries']]
+      entries = _ParseGitilesJson(json_data)['entries']
+      return [e['name'] + ('/' if e['type'] == 'tree' else '') for e in entries]
 
     def fixup_url_format(path):
       # By default, Gitiles URLs display resources in HTML. To get resources
@@ -135,8 +136,8 @@ class GitilesFileSystem(FileSystem):
     return Future(value=())
 
   @memoize
-  def GetCommitID(self):
-    '''Returns a future that resolves to the commit ID for this branch.
+  def _GetCommitInfo(self, key):
+    '''Retrieves a value from the Gitiles JSON commit view.
     '''
     # Commit information for a branch is obtained by appending '?format=JSON'
     # to the branch URL. Note that '<gitiles_url>/<branch>?format=JSON' is
@@ -150,12 +151,24 @@ class GitilesFileSystem(FileSystem):
     #   {
     #     "commit": "8fd578e1a7b142cd10a4387861f05fb9459b69e2", # Commit ID.
     #     "tree": "3ade65d8a91eadd009a6c9feea8f87db2c528a53",   # Tree ID.
+    #     # Previous Commit ID.
+    #     "parents": ["a477c787fe847ae0482329f69b39ce0fde047359"],
     #     "author": {...},
     #     "committer": {...},
     #     "message": <codereview message>,
     #     ...
     #   }
-    return content_future.Then(lambda json: _ParseGitilesJson(json)['commit'])
+    return content_future.Then(lambda json: _ParseGitilesJson(json)[key])
+
+  def GetCommitID(self):
+    '''Returns a future that resolves to the commit ID for this branch.
+    '''
+    return self._GetCommitInfo('commit')
+
+  def GetPreviousCommitID(self):
+    '''Returns a future that resolves to the previous commit ID for this branch.
+    '''
+    return self._GetCommitInfo('parents').Then(lambda parents: parents[0])
 
   def Stat(self, path):
     return self.StatAsync(path).Get()