Re-landing https://chromiumcodereview.appspot.com/11587012: Introduce mac_want_real_dsym GYP flag.

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 234 matching lines @@
       # is useful to integrate a third party phishing/malware detection to
       # existing safe browsing logic.
       'safe_browsing%': 1,
 
       # Speech input is compiled in by default. Set to 0 to disable.
       'input_speech%': 1,
 
       # Notifications are compiled in by default. Set to 0 to disable.
       'notifications%' : 1,
 
+      # Use dsymutil to generate real .dSYM files on Mac. The default is 0 for
+      # regular builds and 1 for ASan builds.
+      'mac_want_real_dsym%': 'default',
+
       # If this is set, the clang plugins used on the buildbot will be used.
       # Run tools/clang/scripts/update.sh to make sure they are compiled.
       # This causes 'clang_chrome_plugins_flags' to be set.
       # Has no effect if 'clang' is not set as well.
       'clang_use_chrome_plugins%': 1,
 
       # Enable building with ASAN (Clang's -fsanitize=address option).
       # -fsanitize=address only works with clang, but asan=1 implies clang=1
       # See https://sites.google.com/a/chromium.org/dev/developers/testing/addresssanitizer
       'asan%': 0,
@@ skipping 405 matching lines @@
     'use_third_party_translations%': '<(use_third_party_translations)',
     'remoting%': '<(remoting)',
     'enable_one_click_signin%': '<(enable_one_click_signin)',
     'enable_webrtc%': '<(enable_webrtc)',
     'chromium_win_pch%': '<(chromium_win_pch)',
     'configuration_policy%': '<(configuration_policy)',
     'safe_browsing%': '<(safe_browsing)',
     'input_speech%': '<(input_speech)',
     'notifications%': '<(notifications)',
     'clang_use_chrome_plugins%': '<(clang_use_chrome_plugins)',
+    'mac_want_real_dsym%': '<(mac_want_real_dsym)',
     'asan%': '<(asan)',
     'tsan%': '<(tsan)',
     'tsan_blacklist%': '<(tsan_blacklist)',
     'clang_type_profiler%': '<(clang_type_profiler)',
     'order_profiling%': '<(order_profiling)',
     'order_text_section%': '<(order_text_section)',
     'enable_extensions%': '<(enable_extensions)',
     'enable_web_intents%': '<(enable_web_intents)',
     'enable_web_intents_tag%': '<(enable_web_intents_tag)',
     'enable_plugin_installation%': '<(enable_plugin_installation)',
@@ skipping 2665 matching lines @@
         ],  # target_conditions
       },  # target_defaults
     }],  # OS=="mac" or OS=="ios"
     ['OS=="mac"', {
       'target_defaults': {
         'variables': {
           # 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.
-          'mac_real_dsym': 0,  # Fake .dSYMs are fine in most cases.
           # Strip debugging symbols from the target.
           'mac_strip': '<(mac_strip_release)',
+          'conditions': [
+            ['asan==1', {
+              'conditions': [
+                ['mac_want_real_dsym=="default"', {
+                  '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)'
+                }],
+              ],
+            }],
+          ],
         },
         'xcode_settings': {
           'GCC_DYNAMIC_NO_PIC': 'NO',               # No -mdynamic-no-pic
                                                     # (Equivalent to -fPIC)
           # MACOSX_DEPLOYMENT_TARGET maps to -mmacosx-version-min
           'MACOSX_DEPLOYMENT_TARGET': '<(mac_deployment_target)',
           # Keep pch files below xcodebuild/.
           'SHARED_PRECOMPS_DIR': '$(CONFIGURATION_BUILD_DIR)/SharedPrecompiledHeaders',
           'OTHER_CFLAGS': [
             '-fno-strict-aliasing',  # See http://crbug.com/32204
@@ skipping 542 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',
   },
 }