Build nacl_helper_nonsfi with GN

ppapi/proxy/BUILD.gn

Index: ppapi/proxy/BUILD.gn
diff --git a/ppapi/proxy/BUILD.gn b/ppapi/proxy/BUILD.gn
index e3bd8c5439c67896ac061385c527a600a1b610f9..7500a744cac879e42c8904e27e4592a1a0d539ec 100644
--- a/ppapi/proxy/BUILD.gn
+++ b/ppapi/proxy/BUILD.gn
@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/nacl/config.gni")
+
 config("proxy_implementation") {
   defines = [ "PPAPI_PROXY_IMPLEMENTATION" ]
 }
@@ -281,7 +283,6 @@ component("proxy") {
     "//ppapi/c",
     "//ppapi/proxy:ipc_sources",
     "//ppapi/shared_impl",
-    "//third_party/icu",
   ]
 
   if (!is_nacl) {
@@ -293,6 +294,10 @@ component("proxy") {
       "//ui/surface",
     ]
   }
+
+  if (!is_nacl_nonsfi) {
+    deps += [ "//third_party/icu" ]
+  }
 }
 
 group("ipc") {