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 76 matching lines @@
     m_destination = AudioDestination::create(*this, m_inputDeviceId, m_numberOfInputChannels, channelCount(), hardwareSampleRate);
 }
 
 void DefaultAudioDestinationNode::startRendering()
 {
     ASSERT(isInitialized());
     if (isInitialized())
         m_destination->start();
 }
 
+void DefaultAudioDestinationNode::stop()
+{
+    ASSERT(isInitialized());
+    if (isInitialized())
+        m_destination->stop();
+}

[haraken, 2014/10/15 15:36:26]

Can we add an ASSERT to verify that start() and stop() are balanced? (i.e.,
start() is not called twice in a row etc)

[Raymond Toy, 2014/10/15 19:50:50]

Added a check that destination is playing when calling stop() and destination is
not playing when calling start().

+
 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
     // send to the audio hardware. It can only be set depending on the maximum number of
     // channels supported by the hardware.
@@ skipping 14 matching lines @@
         // Re-create destination.
         m_destination->stop();
         createDestination();
         m_destination->start();
     }
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)