start/stop method for AudioBufferSourceNodes and OscillatorNodes can take no args.

Source/modules/webaudio/AudioBufferSourceNode.cpp

Index: Source/modules/webaudio/AudioBufferSourceNode.cpp
diff --git a/Source/modules/webaudio/AudioBufferSourceNode.cpp b/Source/modules/webaudio/AudioBufferSourceNode.cpp
index e9bb788e033e897f967969f35a96ee6554fb5b2a..efc3344d5510ed70e9a063f5cb751a6372a322f2 100644
--- a/Source/modules/webaudio/AudioBufferSourceNode.cpp
+++ b/Source/modules/webaudio/AudioBufferSourceNode.cpp
@@ -381,13 +381,17 @@ unsigned AudioBufferSourceNode::numberOfChannels()
     return output(0)->numberOfChannels();
 }
 
-void AudioBufferSourceNode::startGrain(double when, double grainOffset)
+void AudioBufferSourceNode::start(double when)
 {
-    // Duration of 0 has special value, meaning calculate based on the entire buffer's duration.
-    startGrain(when, grainOffset, 0);
+    start(when, 0, buffer()->duration());
 }
 
-void AudioBufferSourceNode::startGrain(double when, double grainOffset, double grainDuration)
+void AudioBufferSourceNode::start(double when, double grainOffset)
+{
+    start(when, grainOffset, buffer()->duration() - grainOffset);
+}
+
+void AudioBufferSourceNode::start(double when, double grainOffset, double grainDuration)
 {
     ASSERT(isMainThread());
 
@@ -404,16 +408,14 @@ void AudioBufferSourceNode::startGrain(double when, double grainOffset, double g
     grainOffset = min(bufferDuration, grainOffset);
     m_grainOffset = grainOffset;
 
-    // Handle default/unspecified duration.
     double maxDuration = bufferDuration - grainOffset;
-    if (!grainDuration)
-        grainDuration = maxDuration;
 
     grainDuration = max(0.0, grainDuration);
     grainDuration = min(maxDuration, grainDuration);
     m_grainDuration = grainDuration;
 
-    m_isGrain = true;
+    // Make this a grain if we're not playing the entire buffer.
+    m_isGrain = m_grainOffset || m_grainDuration != bufferDuration;

[Ken Russell (switch to Gerrit), 2013/10/28 21:32:30]

The == comparison with bufferDuration seems like it will be flaky. Can this be
expressed differently? For example, by continuing to treat a grainDuration of
0.0 as playing the entire buffer?

     m_startTime = when;
 
     // We call timeToSampleFrame here since at playbackRate == 1 we don't want to go through linear interpolation
@@ -427,7 +429,7 @@ void AudioBufferSourceNode::startGrain(double when, double grainOffset, double g
 
 void AudioBufferSourceNode::noteGrainOn(double when, double grainOffset, double grainDuration)
 {
-    startGrain(when, grainOffset, grainDuration);
+    start(when, grainOffset, grainDuration);
 }
 
 double AudioBufferSourceNode::totalPitchRate()