Modify ALLOW_UNUSED to allow enabling unused local warnings on MSVC.

base/logging_unittest.cc

 // Copyright (c) 2011 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 "base/basictypes.h"
 #include "base/logging.h"
 
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 222 matching lines @@
   DCHECK_EQ(some_variable, 1) << "test";
 }
 
 // Test that defining an operator<< for a type in a namespace doesn't prevent
 // other code in that namespace from calling the operator<<(ostream, wstring)
 // defined by logging.h. This can fail if operator<<(ostream, wstring) can't be
 // found by ADL, since defining another operator<< prevents name lookup from
 // looking in the global namespace.
 namespace nested_test {
   class Streamable {};
-  ALLOW_UNUSED std::ostream& operator<<(std::ostream& out, const Streamable&) {
+  ALLOW_UNUSED_TYPE std::ostream& operator<<(std::ostream& out,
+                                             const Streamable&) {
     return out << "Streamable";
   }
   TEST_F(LoggingTest, StreamingWstringFindsCorrectOperator) {
     std::wstring wstr = L"Hello World";
     std::ostringstream ostr;
     ostr << wstr;
     EXPECT_EQ("Hello World", ostr.str());
   }
 }  // namespace nested_test
 
 }  // namespace
 
 }  // namespace logging