Remove redundant null check for AudioBus

Source/core/html/HTMLMediaElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 3737 matching lines @@
         m_client = new HTMLMediaElement::AudioClientImpl(client);
     else
         m_client.clear();
 
     if (m_webAudioSourceProvider)
         m_webAudioSourceProvider->setClient(m_client.get());
 }
 
 void HTMLMediaElement::AudioSourceProviderImpl::provideInput(AudioBus* bus, size_t framesToProcess)
 {
-    // TODO(srirama.m): Investigate whether the bus can be null or not
-    // and remove either ASSERT or null check appropriately.
     ASSERT(bus);
-    if (!bus)
-        return;
 
     MutexTryLocker tryLocker(provideInputLock);
     if (!tryLocker.locked() || !m_webAudioSourceProvider || !m_client.get()) {
         bus->zero();
         return;
     }
 
     // Wrap the AudioBus channel data using WebVector.
     size_t n = bus->numberOfChannels();
     WebVector<float*> webAudioData(n);
@@ skipping 14 matching lines @@
     visitor->trace(m_client);
 }
 
 DEFINE_TRACE(HTMLMediaElement::AudioSourceProviderImpl)
 {
     visitor->trace(m_client);
 }
 #endif
 
 }