Move utility functions for sample rate to AudioUtilities.

Source/platform/audio/AudioUtilities.cpp

Index: Source/platform/audio/AudioUtilities.cpp
diff --git a/Source/platform/audio/AudioUtilities.cpp b/Source/platform/audio/AudioUtilities.cpp
index 531d22d3ed8e4788da6ca2a771fa987434cdb4b2..599cf0a4bf8971350abea917d5f6cd2f0a23e4b8 100644
--- a/Source/platform/audio/AudioUtilities.cpp
+++ b/Source/platform/audio/AudioUtilities.cpp
@@ -27,6 +27,7 @@
 #if ENABLE(WEB_AUDIO)
 
 #include "platform/audio/AudioUtilities.h"
+
 #include "wtf/Assertions.h"
 #include "wtf/MathExtras.h"
 
@@ -59,6 +60,23 @@ 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