Move utility functions for sample rate to AudioUtilities.

Source/platform/audio/AudioUtilities.cpp

 /*
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 #include "config.h"
 
 #if ENABLE(WEB_AUDIO)
 
 #include "platform/audio/AudioUtilities.h"
+
 #include "wtf/Assertions.h"
 #include "wtf/MathExtras.h"
 
 namespace blink {
 
 namespace AudioUtilities {
 
 float decibelsToLinear(float decibels)
 {
     return powf(10, 0.05f * decibels);
@@ skipping 12 matching lines @@
 
 double discreteTimeConstantForSampleRate(double timeConstant, double sampleRate)
 {
     return 1 - exp(-1 / (sampleRate * timeConstant));
 }
 
 size_t timeToSampleFrame(double time, double sampleRate)
 {
     return static_cast<size_t>(round(time * sampleRate));
 }
+
+bool isValidAudioBufferSampleRate(float sampleRate)
+{
+    return sampleRate >= minAudioBufferSampleRate() && sampleRate <= maxAudioBufferSampleRate();
+}
+
+float minAudioBufferSampleRate()
+{
+    // crbug.com/344375
+    return 3000;
+}
+
+float maxAudioBufferSampleRate()
+{
+    // Windows can support up to this rate.

[Raymond Toy, 2014/09/12 15:56:55]

Nit: Not your fault, bu can you update this comment to say:

// Windows can support audio sampling rates this high, so allow AudioBuffer
rates this high as well.

[KhNo, 2014/09/12 16:17:11]

Done.

+    return 192000;
+}
 } // AudioUtilites
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)