Use a valid /prefetch argument when launching a process.

components/nacl/browser/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/config/features.gni")
 
 assert(enable_nacl)
 
 source_set("browser") {
   sources = [
@@ skipping 45 matching lines @@
 
     deps += [
       "//components/nacl/loader:nacl_helper_integration",
       "//sandbox/linux:sandbox_services",
       "//sandbox/linux:suid_sandbox_client",
     ]
 
     data_deps += [ "//components/nacl/loader:helper_nonsfi" ]
   }
 
+  if (is_win) {
+    deps += [
+      # TODO(fdoray): Remove this once the PreRead field trial has expired.
+      # crbug.com/577698
+      "//components/startup_metric_utils/common",
+    ]
+  }
+
   if (is_win && current_cpu == "x86") {
     data_deps += [ "//components/nacl/broker:nacl64" ]
   }
 }