Split "Online" and "Offline" AudioContext processing

Source/modules/webaudio/AudioBufferSourceNode.h

Index: Source/modules/webaudio/AudioBufferSourceNode.h
diff --git a/Source/modules/webaudio/AudioBufferSourceNode.h b/Source/modules/webaudio/AudioBufferSourceNode.h
index f9b093e25afbf11d59e6e34b81592e7a025df94c..38266d8c3877cbfe9fd15c2c9b3480c7507277e1 100644
--- a/Source/modules/webaudio/AudioBufferSourceNode.h
+++ b/Source/modules/webaudio/AudioBufferSourceNode.h
@@ -37,7 +37,7 @@
 
 namespace blink {
 
-class AudioContext;
+class AbstractAudioContext;
 
 // AudioBufferSourceNode is an AudioNode representing an audio source from an in-memory audio asset represented by an AudioBuffer.
 // It generally will be used for short sounds which require a high degree of scheduling flexibility (can playback in rhythmically perfect ways).
@@ -156,7 +156,7 @@ private:
 class AudioBufferSourceNode final : public AudioScheduledSourceNode {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    static AudioBufferSourceNode* create(AudioContext&, float sampleRate);
+    static AudioBufferSourceNode* create(AbstractAudioContext&, float sampleRate);
     DECLARE_VIRTUAL_TRACE();
     AudioBufferSourceHandler& audioBufferSourceHandler() const;
 
@@ -177,7 +177,7 @@ public:
     void start(double when, double grainOffset, double grainDuration, ExceptionState&);
 
 private:
-    AudioBufferSourceNode(AudioContext&, float sampleRate);
+    AudioBufferSourceNode(AbstractAudioContext&, float sampleRate);
 
     Member<AudioParam> m_playbackRate;
     Member<AudioParam> m_detune;