Move WriteFile and WriteFileDescriptor from file_util to base namespace.

chrome/browser/policy/cloud/cloud_policy_browsertest.cc

Index: chrome/browser/policy/cloud/cloud_policy_browsertest.cc
diff --git a/chrome/browser/policy/cloud/cloud_policy_browsertest.cc b/chrome/browser/policy/cloud/cloud_policy_browsertest.cc
index 4c24434869ea4d4f121a26e1695ddd6cae2503ed..16f4c20734f674381e6fc1eb859b609378cd0876 100644
--- a/chrome/browser/policy/cloud/cloud_policy_browsertest.cc
+++ b/chrome/browser/policy/cloud/cloud_policy_browsertest.cc
@@ -246,8 +246,8 @@ class CloudPolicyTest : public InProcessBrowserTest,
   }
 
   void SetServerPolicy(const std::string& policy) {
-    int result = file_util::WriteFile(policy_file_path(), policy.data(),
-                                      policy.size());
+    int result = base::WriteFile(policy_file_path(), policy.data(),
+                                 policy.size());
     ASSERT_EQ(static_cast<int>(policy.size()), result);
   }