supersize: Fix diff logic for changed vs unchanged of groups

tools/binary_size/diagnose_bloat.py

 #!/usr/bin/env python
 # Copyright 2017 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.
 
 """Tool for finding the cause of binary size bloat.
 
 See //tools/binary_size/README.md for example usage.
 
 Note: this tool will perform gclient sync/git checkout on your local repo if
@@ skipping 59 matching lines @@
     """Prepare a binary size diff with ready to print results."""
     raise NotImplementedError()
 
   def RunDiff(self, logfile, before_dir, after_dir):
     logging.info('Creating: %s', self.name)
     self.ProduceDiff(before_dir, after_dir)
     self.AppendResults(logfile)
 
 
 class NativeDiff(BaseDiff):
-  _RE_SUMMARY = re.compile(
-      r'.*(Section Sizes .*? object files added, \d+ removed).*',
-      flags=re.DOTALL)
+  _RE_SUMMARY = re.compile(r'Section Sizes .*?\n\n.*?(?=\n\n)', flags=re.DOTALL)
   _RE_SUMMARY_STAT = re.compile(
       r'Section Sizes \(Total=(?P<value>\d+) (?P<units>\w+)\)')
   _SUMMARY_STAT_NAME = 'Native Library Delta'
 
   def __init__(self, size_name, supersize_path):
     self._size_name = size_name
     self._supersize_path = supersize_path
     self._diff = []
     super(NativeDiff, self).__init__('Native Diff')
 
   @property
   def summary_stat(self):
     m = NativeDiff._RE_SUMMARY_STAT.search(self._diff)
     if m:
       return _DiffResult(
           NativeDiff._SUMMARY_STAT_NAME, m.group('value'), m.group('units'))
     return None
 
   def DetailedResults(self):
     return self._diff.splitlines()
 
   def Summary(self):
-    return NativeDiff._RE_SUMMARY.match(self._diff).group(1)
+    return NativeDiff._RE_SUMMARY.search(self._diff).group()
 
   def ProduceDiff(self, before_dir, after_dir):
     before_size = os.path.join(before_dir, self._size_name)
     after_size = os.path.join(after_dir, self._size_name)
     cmd = [self._supersize_path, 'diff', before_size, after_size]
     self._diff = _RunCmd(cmd)[0].replace('{', '{{').replace('}', '}}')
 
 
 class ResourceSizesDiff(BaseDiff):
   _RESOURCE_SIZES_PATH = os.path.join(
@@ skipping 690 matching lines @@
 
       if i != 0:
         diff_mngr.MaybeDiff(i - 1, i)
 
     diff_mngr.Summarize()
 
 
 if __name__ == '__main__':
   sys.exit(main())