Fix GN NaCl Debug build of base.

base/json/BUILD.gn

Index: base/json/BUILD.gn
diff --git a/base/json/BUILD.gn b/base/json/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..0310ea9460c2520fefe7863cb377e2db858bb921
--- /dev/null
+++ b/base/json/BUILD.gn
@@ -0,0 +1,37 @@
+# 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.
+
+source_set("json") {
+  sources = [
+    "json_file_value_serializer.cc",
+    "json_file_value_serializer.h",
+    "json_parser.cc",
+    "json_parser.h",
+    "json_reader.cc",
+    "json_reader.h",
+    "json_string_value_serializer.cc",
+    "json_string_value_serializer.h",
+    "json_value_converter.cc",
+    "json_value_converter.h",
+    "json_writer.cc",
+    "json_writer.h",
+    "string_escape.cc",
+    "string_escape.h",
+  ]
+
+  if (is_nacl) {
+    sources -= [
+      "json_file_value_serializer.cc",
+      "json_file_value_serializer.h",
+    ]
+  }
+
+  defines = [ "BASE_IMPLEMENTATION" ]
+
+  deps = [
+    "//base/memory",
+  ]
+
+  visibility = [ "//base/*" ]
+}