Reverts fdca07 and makes it possible to force absolute paths.

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/build_metadata.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
 import("//build/toolchain/goma.gni")
 
 declare_args() {
   # When set (the default) enables C++ iterator debugging in debug builds.
   # Iterator debugging is always off in release builds (technically, this flag
   # affects the "debug" config, which is always available but applied by
   # default only in debug builds).
   #
   # Iterator debugging is generally useful for catching bugs. But it can
   # introduce extra locking to check the state of an iterator against the state
   # of the current object. For iterator- and thread-heavy code, this can
   # significantly slow execution.
   enable_iterator_debugging = true
 
-  # 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
-
   # Set to true to enable dcheck in Release builds.
   dcheck_always_on = false
 }
 
 # TODO(brettw) Most of these should be removed. Instead of global feature
 # flags, we should have more modular flags that apply only to a target and its
 # dependents. For example, depending on the "x11" meta-target should define
 # USE_X11 for all dependents so that everything that could use X11 gets the
 # define, but anything that doesn't depend on X11 doesn't see it.
 #
@@ skipping 428 matching lines @@
     # This error doesn't happen every time. In VS2013, it seems if the .pch
     # file doesn't exist, no error will be generated (probably MS tested this
     # case but forgot the other one?). To reproduce this error, do a build,
     # then delete the precompile.c.obj file, then build again.
     cflags_c = [ "/wd4206" ]
   } else if (is_mac && !is_official_build && !use_goma) {
     precompiled_header = "build/precompile.h"
     precompiled_source = "//build/precompile.h"
   }
 }