Convert RLZ to a buildflag header

components/BUILD.gn

 # Copyright 2014 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")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//printing/features/features.gni")
+import("//rlz/features/features.gni")
 import("//testing/test.gni")
 import("//tools/grit/repack.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
 if (is_ios) {
   import("//ios/build/config.gni")
 }
@@ skipping 479 matching lines @@
       "//testing/perf",
       "//url",
     ]
 
     if (!is_ios) {
       sources += [ "discardable_memory/common/discardable_shared_memory_heap_perftest.cc" ]
       deps += [ "//components/discardable_memory/common" ]
     }
   }
 }