Implement suspend/resume for AudioContext

Source/modules/webaudio/DefaultAudioDestinationNode.cpp

 /*
  * Copyright (C) 2011, Google 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 72 matching lines @@
 {
     float hardwareSampleRate = AudioDestination::hardwareSampleRate();
     WTF_LOG(WebAudio, ">>>> hardwareSampleRate = %f\n", hardwareSampleRate);
 
     m_destination = AudioDestination::create(*this, m_inputDeviceId, m_numberOfInputChannels, channelCount(), hardwareSampleRate);
 }
 
 void DefaultAudioDestinationNode::startRendering()
 {
     ASSERT(isInitialized());
-    if (isInitialized())
+    if (isInitialized()) {
+        ASSERT(!m_destination->isPlaying());
         m_destination->start();
+    }
+}
+
+void DefaultAudioDestinationNode::stopRendering()
+{
+    ASSERT(isInitialized());
+    if (isInitialized()) {
+        ASSERT(m_destination->isPlaying());
+        m_destination->stop();
+    }
 }
 
 unsigned long DefaultAudioDestinationNode::maxChannelCount() const
 {
     return AudioDestination::maxChannelCount();
 }
 
 void DefaultAudioDestinationNode::setChannelCount(unsigned long channelCount, ExceptionState& exceptionState)
 {
     // The channelCount for the input to this node controls the actual number of channels we
@@ skipping 16 matching lines @@
         // Re-create destination.
         m_destination->stop();
         createDestination();
         m_destination->start();
     }
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)