Improve input handling for WaveAudioHandler.

media/audio/sounds/sounds_manager.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/audio/sounds/sounds_manager.h"
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
@@ skipping 71 matching lines @@
   return true;
 }
 
 base::TimeDelta SoundsManagerImpl::GetDuration(SoundKey key) {
   DCHECK(CalledOnValidThread());
   linked_ptr<AudioStreamHandler> handler = GetHandler(key);
   if (!handler.get())
       return base::TimeDelta();
   if (!handler->IsInitialized())
     return base::TimeDelta();
-  const WavAudioHandler& wav_audio = handler->wav_audio_handler();
-  return wav_audio.GetDuration();
+
+  const WavAudioHandler* wav_audio = handler->wav_audio_handler();
+  DCHECK(wav_audio);
+  return wav_audio->GetDuration();
 }
 
 linked_ptr<AudioStreamHandler> SoundsManagerImpl::GetHandler(SoundKey key) {
   auto key_handler_pair_iter = handlers_.find(key);
   return key_handler_pair_iter == handlers_.end() ?
       linked_ptr<AudioStreamHandler>() : key_handler_pair_iter->second;
 }
 
 }  // namespace
 
@@ skipping 26 matching lines @@
 
 // static
 void SoundsManager::InitializeForTesting(SoundsManager* manager) {
   CHECK(!g_instance) << "SoundsManager is already initialized.";
   CHECK(manager);
   g_instance = manager;
   g_initialized_for_testing = true;
 }
 
 }  // namespace media