Extensions: Fix DocServer assert failures.

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

Index: chrome/common/extensions/docs/server2/availability_finder.py
diff --git a/chrome/common/extensions/docs/server2/availability_finder.py b/chrome/common/extensions/docs/server2/availability_finder.py
index 35a9df1ad9f4fb902821df7cb57da60e11c2d34d..e8f6bc6dbf9717dbbba32d2f13f7ec8212ba311b 100644
--- a/chrome/common/extensions/docs/server2/availability_finder.py
+++ b/chrome/common/extensions/docs/server2/availability_finder.py
@@ -144,11 +144,12 @@ class AvailabilityFinder(object):
         JSON_TEMPLATES + 'api_availabilities.json').Get().get(node_name)
     if node_info is None:
       return None
-    if node_info['channel'] == 'stable':
-      return AvailabilityInfo(
-          self._branch_utility.GetStableChannelInfo(node_info['version']))
-    return AvailabilityInfo(
-        self._branch_utility.GetChannelInfo(node_info['channel']))
+
+    channel_info = self._branch_utility.GetStableChannelInfo(
+        node_info['version']) if node_info['channel'] == 'stable' \
+        else self._branch_utility.GetChannelInfo(node_info['channel'])

[karandeepb, 2017/03/10 03:13:37]

This is required for issue 700234. I haven't dived much into this code, but it
seems that for some older APIs, if the info is not available through
https://omahaproxy.appspot.com/history.json?channel=dev&os=win&json=1, our logic
shows them as available from the least version for which info. is available.

Hence for Webstore API, it'll show as available from Version 16 (Actual should
be 15). This also seems to be the case for multiple other APIs. See
https://developer.chrome.com/extensions/api_index where many APIs are available
since Chrome 15, which is probably incorrect. 

+
+    return AvailabilityInfo(channel_info) if channel_info else None
 
   @memoize
   def _CreateAPISchemaFileSystem(self, file_system):