Move base GN subprojects into base.

base/trace_event/etw_manifest/BUILD.gn

 # Copyright 2015 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/win/message_compiler.gni")
 
 assert(is_win, "This only runs on Windows.")
 
 message_compiler("chrome_events_win") {
   visibility = [
-    "//base/trace_event/*",
+    "//base/*",
     "//chrome:main_dll",
   ]
 
   sources = [
     "chrome_events_win.man",
   ]
 
   user_mode_logging = true
 
   # TOOD(brucedawson) bug 569989: Enable ETW manifest and compile and link it
   # into the proper places. Enabling as-is may add the resources to too many
   # targets. See the bug for more information.
   compile_generated_code = false
 }