Fix attributes types on AnalyserNode as specification of web audio.

Source/modules/webaudio/AnalyserNode.h

Index: Source/modules/webaudio/AnalyserNode.h
diff --git a/Source/modules/webaudio/AnalyserNode.h b/Source/modules/webaudio/AnalyserNode.h
index 10a0e8aa7c7a66211c1100502c14ab8e339008a6..6c7ecaf0829c61de48acebf537d868a6cd3ed25d 100644
--- a/Source/modules/webaudio/AnalyserNode.h
+++ b/Source/modules/webaudio/AnalyserNode.h
@@ -51,14 +51,14 @@ public:
 
     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); }