Reverts fdca07 and makes it possible to force absolute paths.

build/config/build_metadata.gni

Index: build/config/build_metadata.gni
diff --git a/build/config/build_metadata.gni b/build/config/build_metadata.gni
new file mode 100644
index 0000000000000000000000000000000000000000..befacbc54d7079cf8b776be90e685ed62635f911
--- /dev/null
+++ b/build/config/build_metadata.gni
@@ -0,0 +1,18 @@
+# Copyright (c) 2016 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/chrome_build.gni")
+
+declare_args() {
+  # Set to true to not store any build metadata, e.g. ifdef out all __DATE__
+  # and __TIME__. Set to 0 to reenable the use of these macros in the code
+  # base. See http://crbug.com/314403.
+  #
+  # Continue to embed build meta data in Official builds, basically the
+  # time it was built.
+  # TODO(maruel): This decision should be revisited because having an
+  # official deterministic build has high value too but MSVC toolset can't
+  # generate anything deterministic with WPO enabled AFAIK.
+  dont_embed_build_metadata = !is_official_build
+}