Add WebKit API to retrieve the audio hardware sample-rate

media/audio/audio_util.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Software adjust volume of samples, allows each audio stream its own
 // volume without impacting master volume for chrome and other applications.
 
 // Implemented as templates to allow 8, 16 and 32 bit implementations.
 // 8 bit is unsigned and biased by 128.
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "media/audio/audio_util.h"
+#if defined(OS_MACOSX)
+#include "media/audio/mac/audio_low_latency_output_mac.h"
+#endif
 
 namespace media {
 
 // TODO(fbarchard): Convert to intrinsics for better efficiency.
 template<class Fixed>
 static int ScaleChannel(int channel, int volume) {
   return static_cast<int>((static_cast<Fixed>(channel) * volume) >> 16);
 }
 
 template<class Format, class Fixed, int bias>
@@ skipping 188 matching lines @@
       if (sample < -32768.0)
         sample = -32768.0;
       else if (sample > 32767.0)
         sample = 32767.0;
 
       destination[j * channels + i] = static_cast<int16>(sample);
     }
   }
 }
 
+double GetAudioHardwareSampleRate()
+{

[scherkus (not reviewing), 2011/03/23 04:57:57]

nit: chromium style has brackets go on the function

+#if defined(OS_MACOSX)
+    // Hardware sample-rate on the Mac can be configured, so we must query.

[scherkus (not reviewing), 2011/03/23 04:57:57]

nit: two space indent

+    return AUAudioOutputStream::HardwareSampleRate();
+#else
+    // Hardware for Windows and Linux is nearly always 48KHz.
+    // TODO(crogers) : return correct value in rare non-48KHz cases.

[scherkus (not reviewing), 2011/03/23 04:57:57]

this isn't quite true... in fact chrome os was shipping with 44.1khz default (I
think) but we're changing it back to 48khz

do you have any intention on implementing this?  can we get a bug filed?

+    return 48000.0;
+#endif
+}
+
 }  // namespace media