Adds ability to build for asan with gn

build/config/BUILD.gn

 # Copyright (c) 2013 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.
 
 import("//build/config/allocator.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 
 declare_args() {
@@ skipping 104 matching lines @@
   }
   if (use_x11) {
     defines += [ "USE_X11=1" ]
     if (use_xi2_mt > 0) {
       defines += [ "USE_XI2_MT=$use_xi2_mt" ]
     }
   }
   if (use_allocator != "tcmalloc") {
     defines += [ "NO_TCMALLOC" ]
   }
+  if (is_asan) {
+    defines += [
+      "ADDRESS_SANITIZER",
+      "MEMORY_TOOL_REPLACES_ALLOCATOR",
+      "MEMORY_SANITIZER_INITIAL_SIZE",
+    ]
+  }
   if (enable_webrtc) {
     defines += [ "ENABLE_WEBRTC=1" ]
   }
   if (disable_ftp_support) {
     defines += [ "DISABLE_FTP_SUPPORT=1" ]
   }
   if (!enable_nacl) {
     defines += [ "DISABLE_NACL" ]
   }
   if (enable_extensions) {
@@ skipping 158 matching lines @@
       "CoreText.framework",
       "Foundation.framework",
       "UIKit.framework",
     ]
   } else if (is_linux) {
     libs = [
       "dl",
     ]
   }
 }