Fix attributes types on AnalyserNode as specification of web audio.

Source/modules/webaudio/AnalyserNode.h

 /*
  * Copyright (C) 2010, 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 33 matching lines @@
 
     // AudioNode
     virtual void process(size_t framesToProcess) OVERRIDE;
 
     // Javascript bindings
     unsigned fftSize() const { return m_analyser.fftSize(); }
     void setFftSize(unsigned size, ExceptionState&);
 
     unsigned frequencyBinCount() const { return m_analyser.frequencyBinCount(); }
 
-    void setMinDecibels(float k, ExceptionState&);
-    float minDecibels() const { return m_analyser.minDecibels(); }
+    void setMinDecibels(double k, ExceptionState&);
+    double minDecibels() const { return m_analyser.minDecibels(); }
 
-    void setMaxDecibels(float k, ExceptionState&);
-    float maxDecibels() const { return m_analyser.maxDecibels(); }
+    void setMaxDecibels(double k, ExceptionState&);
+    double maxDecibels() const { return m_analyser.maxDecibels(); }
 
-    void setSmoothingTimeConstant(float k, ExceptionState&);
-    float smoothingTimeConstant() const { return m_analyser.smoothingTimeConstant(); }
+    void setSmoothingTimeConstant(double k, ExceptionState&);
+    double smoothingTimeConstant() const { return m_analyser.smoothingTimeConstant(); }
 
     void getFloatFrequencyData(Float32Array* array) { m_analyser.getFloatFrequencyData(array); }
     void getByteFrequencyData(Uint8Array* array) { m_analyser.getByteFrequencyData(array); }
     void getFloatTimeDomainData(Float32Array* array) { m_analyser.getFloatTimeDomainData(array); }
     void getByteTimeDomainData(Uint8Array* array) { m_analyser.getByteTimeDomainData(array); }
 private:
     virtual double tailTime() const OVERRIDE { return 0; }
     virtual double latencyTime() const OVERRIDE { return 0; }
 
     AnalyserNode(AudioContext*, float sampleRate);
 
     RealtimeAnalyser m_analyser;
 };
 
 } // namespace WebCore
 
 #endif // AnalyserNode_h