Clean up audio-related utility functions to compute buffer sizes

content/renderer/media/audio_hardware.h

Index: content/renderer/media/audio_hardware.h
diff --git a/content/renderer/media/audio_hardware.h b/content/renderer/media/audio_hardware.h
index ea9a28a61ed57b4f7b8c0c293b34ef93e3d62ac2..19edb8cb2e426efa89fdfdda0f32976e6afd29d6 100644
--- a/content/renderer/media/audio_hardware.h
+++ b/content/renderer/media/audio_hardware.h
@@ -24,8 +24,13 @@ CONTENT_EXPORT double GetInputSampleRate();
 
 // Fetch the buffer size we use for the default output device.
 // Must be called from RenderThreadImpl::current().
+// Must be used in conjunction with AUDIO_PCM_LOW_LATENCY.
 CONTENT_EXPORT size_t GetOutputBufferSize();
 
+// Computes a buffer size based on the given |sample_rate|. Must be used in
+// conjunction with AUDIO_PCM_LINEAR.
+CONTENT_EXPORT size_t GetHighLatencyOutputBufferSize(int sample_rate);
+
 // Fetch the number of audio channels for the default input device.
 // Must be called from RenderThreadImpl::current().
 CONTENT_EXPORT uint32 GetInputChannelCount();