Do not enforce the public API presubmit check for Revert CLs

PRESUBMIT.py

Index: PRESUBMIT.py
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index cf46862354d71cb7d00c5bb0098b568237f6be33..bdcf0ad087b49ecdaacdd6586c449b31e9b89274 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -13,6 +13,8 @@ import os
 import sys
 
 
+REVERT_CL_SUBJECT_PREFIX = 'Revert of '
+
 SKIA_TREE_STATUS_URL = 'http://skia-tree-status.appspot.com'
 
 PUBLIC_API_OWNERS = (
@@ -20,7 +22,6 @@ PUBLIC_API_OWNERS = (
     'reed@google.com',
     'bsalomon@chromium.org',
     'bsalomon@google.com',
-    'rmistry@google.com',  # For emergency reverts only.
 )
 
 
@@ -127,6 +128,9 @@ def _CheckLGTMsForPublicAPI(input_api, output_api):
   if issue and input_api.rietveld:
     issue_properties = input_api.rietveld.get_issue_properties(
         issue=int(issue), messages=True)
+    if issue_properties['subject'].startswith(REVERT_CL_SUBJECT_PREFIX):
+      # It is a revert CL, ignore the public api owners check.
+      return results

[borenet, 2014/01/31 16:21:58]

Seems like there should be a more robust way of doing this.  It's a little scary
to depend on the Rietveld format.

[rmistry, 2014/01/31 16:24:00]

Which format? the format of the subject? there is really no other way of
determining it is a CL generated by one-click revert. I also made the variable
name generic to hint that it could be applied to any CL created with 'Revert of'
subject prefix.

[borenet, 2014/01/31 16:27:36]

Yeah.  I think this is okay, but I wish there was a better way.  For the record,
I see a lot of manual revert CLs which use this formats:

Revert "Original subject"
Revert 11234

So it may be better to change the prefix to just "Revert" (and maybe not worry
about case)

[rmistry, 2014/01/31 17:29:42]

That makes sense, done.

     if issue_properties['owner_email'] in PUBLIC_API_OWNERS:
       # An owner created the CL that is an automatic LGTM.
       lgtm_from_owner = True
@@ -139,7 +143,7 @@ def _CheckLGTMsForPublicAPI(input_api, output_api):
           # Found an lgtm in a message from an owner.
           lgtm_from_owner = True
           break;
-       
+
   if not lgtm_from_owner:
     results.append(
         output_api.PresubmitError(