Align base::hash_map with C++11, part 2.

mojo/edk/system/channel_endpoint_id.h

 // Copyright 2014 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.
 
 #ifndef MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_ID_H_
 #define MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_ID_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <ostream>
 
 #include "base/containers/hash_tables.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
-#include "build/build_config.h"
 #include "mojo/edk/system/system_impl_export.h"
 
 namespace mojo {
 namespace system {
 
 // ChannelEndpointId -----------------------------------------------------------
 
 class LocalChannelEndpointIdGenerator;
 FORWARD_DECLARE_TEST(LocalChannelEndpointIdGeneratorTest, WrapAround);
 FORWARD_DECLARE_TEST(RemoteChannelEndpointIdGeneratorTest, WrapAround);
@@ skipping 99 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(RemoteChannelEndpointIdGenerator);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 // Define "hash" functions for |ChannelEndpointId|s, so they can be used in hash
 // tables.
 // TODO(vtl): Once we can use |std::unordered_{map,set}|, update this (and
-// remove the base/containers/hash_tables.h and build/build_config.h includes).
+// remove the base/containers/hash_tables.h include).
 namespace BASE_HASH_NAMESPACE {
 
-#if defined(COMPILER_GCC)
-
 template <>
 struct hash<mojo::system::ChannelEndpointId> {
   size_t operator()(mojo::system::ChannelEndpointId channel_endpoint_id) const {
     return static_cast<size_t>(channel_endpoint_id.value());
   }
 };
 
-#elif defined(COMPILER_MSVC)
-
-inline size_t hash_value(mojo::system::ChannelEndpointId channel_endpoint_id) {
-  return static_cast<size_t>(channel_endpoint_id.value());
-}
-#endif
-
 }  // namespace BASE_HASH_NAMESPACE
 
 #endif  // MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_ID_H_