[Sync] Replace typedef with using.

components/sync/base/proto_value_ptr_unittest.cc

 // 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.
 
 #include "components/sync/base/proto_value_ptr.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/macros.h"
@@ skipping 95 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(TestValue);
 };
 
 // Static initializers.
 int TestValue::g_copy_count = 0;
 int TestValue::g_parse_count = 0;
 int TestValue::g_delete_count = 0;
 
 }  // namespace
 
-typedef ProtoValuePtr<TestValue> TestPtr;
+using TestPtr = ProtoValuePtr<TestValue>;
 
 class ProtoValuePtrTest : public testing::Test {
  public:
   void SetUp() override { TestValue::ResetCounters(); }
 
   static bool WrappedValuesAreShared(const TestPtr& ptr1, const TestPtr& ptr2) {
     const TestValue& wrapped_value_1 = ptr1.value();
     const TestValue& wrapped_value_2 = ptr2.value();
     // Compare addresses.
     return &wrapped_value_1 == &wrapped_value_2;
@@ skipping 113 matching lines @@
     EXPECT_EQ(1, TestValue::parse_count());
     EXPECT_EQ(0, TestValue::copy_count());
 
     EXPECT_EQ(v1, ptr1->value());
   }
 
   EXPECT_EQ(1, TestValue::delete_count());
 }
 
 }  // namespace syncer