Land prep work to enable NaCl in the Linux x64 GN builds.

url/BUILD.gn

Index: url/BUILD.gn
diff --git a/url/BUILD.gn b/url/BUILD.gn
index 964a08bde6a4e1ef68c2d72912b5d5aef299f0e5..95428069a8b3eeceebd0104abae17920e431616b 100644
--- a/url/BUILD.gn
+++ b/url/BUILD.gn
@@ -60,17 +60,21 @@ component("url") {
 
   configs += [
     ":url_icu_config",
+
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 
   deps = [
     "//base",
-    "//base/third_party/dynamic_annotations",
     "//third_party/icu:icudata",
     "//third_party/icu",
   ]
 
+  if (!is_nacl) {
+    deps += [ "//base/third_party/dynamic_annotations" ]
+  }
+
   if (use_icu_alternatives_on_android) {
     sources -= [
       "url_canon_icu.cc",