Remove base::Value::CreateNullValue

extensions/common/permissions/manifest_permission_set_unittest.cc

 // Copyright 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.
 
+#include "extensions/common/permissions/manifest_permission_set.h"
+
+#include "base/memory/ptr_util.h"
 #include "base/pickle.h"
 #include "base/values.h"
 #include "extensions/common/permissions/manifest_permission.h"
-#include "extensions/common/permissions/manifest_permission_set.h"
 #include "ipc/ipc_message.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace extensions {
 
 class MockManifestPermission : public ManifestPermission {
  public:
   MockManifestPermission(const std::string& name)
       : name_(name) {
   }
 
   std::string name() const override { return name_; }
 
   std::string id() const override { return name(); }
 
   PermissionIDSet GetPermissions() const override { return PermissionIDSet(); }
 
   bool FromValue(const base::Value* value) override { return true; }
 
   std::unique_ptr<base::Value> ToValue() const override {
-    return base::Value::CreateNullValue();
+    return base::MakeUnique<base::Value>();
   }
 
   ManifestPermission* Diff(const ManifestPermission* rhs) const override {
     const MockManifestPermission* other =
         static_cast<const MockManifestPermission*>(rhs);
     EXPECT_EQ(name_, other->name_);
     return NULL;
   }
 
   ManifestPermission* Union(const ManifestPermission* rhs) const override {
@@ skipping 173 matching lines @@
   EXPECT_EQ(expected_permissions, result);
 
   // |result| = |permissions1| - |permissions2| -->
   //   |result| intersect |permissions2| == empty_set
   ManifestPermissionSet result2;
   ManifestPermissionSet::Intersection(result, permissions2, &result2);
   EXPECT_TRUE(result2.empty());
 }
 
 }  // namespace extensions