Use real dSYM files for ASan Mac builds by default.

build/common.gypi

 # Copyright (c) 2012 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 3356 matching lines @@
           # These should end with %, but there seems to be a bug with % in
           # variables that are intended to be set to different values in
           # different targets, like these.
           'mac_pie': 1,        # Most executables can be position-independent.
           # Strip debugging symbols from the target.
           'mac_strip': '<(mac_strip_release)',
           'conditions': [
             ['asan==1', {
               'conditions': [
                 ['mac_want_real_dsym=="default"', {
-                  # TODO(glider): use real dSYM files for ASan once
-                  # http://crbug.com/166857 is fixed.
-                  'mac_real_dsym': 0,
+                  'mac_real_dsym': 1,
                 }, {
                   'mac_real_dsym': '<(mac_want_real_dsym)'
                 }],
               ],
             }, {
               'conditions': [
                 ['mac_want_real_dsym=="default"', {
                   'mac_real_dsym': 0, # Fake .dSYMs are fine in most cases.
                 }, {
                   'mac_real_dsym': '<(mac_want_real_dsym)'
@@ skipping 563 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }