Add enable_ipc_logging build argument

ipc/BUILD.gn

 # Copyright (c) 2012 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/buildflag_header.gni")
 import("//build/config/nacl/config.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 import("//tools/ipc_fuzzer/ipc_fuzzer.gni")
 
+declare_args() {
+  # Enabling debug builds automatically sets enable_ipc_logging to true.
+  enable_ipc_logging = is_debug
+}
+
+buildflag_header("ipc_features") {
+  header = "ipc_features.h"
+
+  flags = [ "IPC_MESSAGE_LOG_ENABLED=$enable_ipc_logging" ]
+}
+
 component("ipc") {
   sources = [
     "export_template.h",
     "handle_attachment_win.cc",
     "handle_attachment_win.h",
     "handle_win.cc",
     "handle_win.h",
     "ipc_channel.cc",
     "ipc_channel.h",
     "ipc_channel_common.cc",
@@ skipping 71 matching lines @@
   } else {
     sources -= [
       "ipc_channel_nacl.cc",
       "ipc_channel_nacl.h",
     ]
   }
 
   defines = [ "IPC_IMPLEMENTATION" ]
 
   public_deps = [
+    ":ipc_features",
     ":mojom",
     ":param_traits",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/system",
   ]
   deps = [
     "//base",
   ]
 
   if (is_win || is_mac) {
@@ skipping 125 matching lines @@
       ":ipc",
     ]
     deps = [
       "//base",
       "//base/test:test_support",
       "//mojo/edk/test:test_support",
       "//testing/gtest",
     ]
   }
 }