Make __DATE__, __TIME__ and __TIMESTAMP__ to evaluate to an empty string.

build/config/compiler/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/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 201 matching lines @@
     # Linker warnings.
     if (fatal_linker_warnings && !(is_chromeos && current_cpu == "arm") &&
         !(is_android && use_order_profiling) && !is_mac && !is_ios) {
       # TODO(jochen): Enable this on chromeos on arm. http://crbug.com/356580
       # TODO(lizeb,pasko): Fix link errors when linking with order_profiling=1
       # crbug.com/485542
       ldflags += [ "-Wl,--fatal-warnings" ]
     }
   }
 
+  # Eliminate build metadata (__DATE__, __TIME__ and __TIMESTAMP__) for
+  # deterministic build.  See https://crbug.com/314403
+  if (!is_official_build) {
+    if (is_win && !is_clang) {
+      cflags += [
+        "/wd4117",  # Trying to define or undefine a predefined macro.
+        "/D__DATE__=",
+        "/D__TIME__=",
+        "/D__TIMESTAMP__=",
+      ]
+    } else {
+      cflags += [
+        "-Wno-builtin-macro-redefined",
+        "-D__DATE__=",
+        "-D__TIME__=",
+        "-D__TIMESTAMP__=",
+      ]
+    }
+  }
+
   if (is_clang && is_debug) {
     # Allow comparing the address of references and 'this' against 0
     # in debug builds. Technically, these can never be null in
     # well-defined C/C++ and Clang can optimize such checks away in
     # release builds, but they may be used in asserts in debug builds.
     cflags_cc += [
       "-Wno-undefined-bool-conversion",
       "-Wno-tautological-undefined-compare",
     ]
   }
@@ skipping 1443 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }