Unify UUID/GUID generation code across base and blink

base/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.
 
 # HOW TO WRITE CONDITIONALS IN THIS FILE
 # ======================================
 #
 # In many other places, one would write a conditional that expresses all the
 # cases when a source file is used or unused, and then either add or subtract
 # it from the sources list in that case
@@ skipping 327 matching lines @@
     "files/memory_mapped_file_posix.cc",
     "files/memory_mapped_file_win.cc",
     "files/scoped_file.cc",
     "files/scoped_file.h",
     "files/scoped_temp_dir.cc",
     "files/scoped_temp_dir.h",
     "format_macros.h",
     "gtest_prod_util.h",
     "guid.cc",
     "guid.h",
-    "guid_posix.cc",
-    "guid_win.cc",
     "hash.cc",
     "hash.h",
     "id_map.h",
     "ios/crb_protocol_observers.h",
     "ios/crb_protocol_observers.mm",
     "ios/device_util.h",
     "ios/device_util.mm",
     "ios/ios_util.h",
     "ios/ios_util.mm",
     "ios/ns_error_util.h",
@@ skipping 2004 matching lines @@
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
     deps = [
       ":base_java",
     ]
     java_files =
         [ "test/android/java/src/org/chromium/base/ContentUriTestUtils.java" ]
   }
 }