diagnose_bloat.py: add missing GN arg for local Linux builds.

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 231 matching lines @@
                              str(multiprocessing.cpu_count()))
     if not self.max_jobs:
       self.max_jobs = '10000' if self.use_goma else '500'
 
     if os.path.exists(os.path.join(os.path.dirname(_SRC_ROOT), 'src-internal')):
       self.extra_gn_args_str = ' is_chrome_branded=true'
     else:
       self.extra_gn_args_str = (' exclude_unwind_tables=true '
           'ffmpeg_branding="Chrome" proprietary_codecs=true')
     if self.IsLinux():
-      self.extra_gn_args_str += ' allow_posix_link_time_opt=false'
+      self.extra_gn_args_str += (
+          ' allow_posix_link_time_opt=false generate_linker_map=true')
     self.target = self.target if self.IsAndroid() else 'chrome'
 
   def _GenGnCmd(self):
     gn_args = 'is_official_build=true symbol_level=1'
     gn_args += ' use_goma=%s' % str(self.use_goma).lower()
     gn_args += ' target_os="%s"' % self.target_os
     if self.IsAndroid():
       gn_args += (' enable_chrome_android_internal=%s' %
                   str(self.enable_chrome_android_internal).lower())
     gn_args += self.extra_gn_args_str
@@ skipping 548 matching lines @@
 
       if i != 0:
         diff_mngr.MaybeDiff(i - 1, i)
 
     diff_mngr.Summarize()
 
 
 if __name__ == '__main__':
   sys.exit(main())