Enforce WARN_UNUSED_RESULT attribute on Windows

media/midi/midi_manager_win.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 "media/midi/midi_manager_win.h"
 
 #include <windows.h>
 #include <ks.h>
 #include <ksmedia.h>
 #include <mmreg.h>
 // Prevent unnecessary functions from being included from <mmsystem.h>
 #define MMNODRV
 #define MMNOSOUND
 #define MMNOWAVE
 #define MMNOAUX
 #define MMNOMIXER
 #define MMNOTIMER
 #define MMNOJOY
 #define MMNOMCI
 #define MMNOMMIO
 #include <mmsystem.h>
 
 #include <algorithm>
 #include <functional>
 #include <queue>
 #include <string>
 
 #include "base/bind.h"
 #include "base/containers/hash_tables.h"
+#include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/system_monitor/system_monitor.h"
 #include "base/threading/thread_checker.h"
 #include "base/timer/timer.h"
 #include "base/win/message_window.h"
@@ skipping 121 matching lines @@
                 << GetOutErrorMessage(result);
     result = midiOutUnprepareHeader(midi_out_handle, midi_header.get(),
                                     sizeof(*midi_header));
     DLOG_IF(ERROR, result != MMSYSERR_NOERROR)
         << "Failed to uninitialize output buffer: "
         << GetOutErrorMessage(result);
     return;
   }
 
   // The ownership of |midi_header| is moved to MOM_DONE event handler.
-  midi_header.release();
+  ignore_result(midi_header.release());
 }
 
 template <size_t array_size>
 base::string16 AsString16(const wchar_t(&buffer)[array_size]) {
   size_t len = 0;
   for (len = 0; len < array_size; ++len) {
     if (buffer[len] == L'\0')
       break;
   }
   return base::string16(buffer, len);
@@ skipping 993 matching lines @@
                                        base::TimeTicks time) {
   ReceiveMidiData(port_index, &data[0], data.size(), time);
 }
 
 MidiManager* MidiManager::Create() {
   return new MidiManagerWin();
 }
 
 }  // namespace midi
 }  // namespace media