Allow audio system to handle synchronized low-latency audio I/O

media/base/audio_bus.h

Index: media/base/audio_bus.h
===================================================================
--- media/base/audio_bus.h	(revision 155437)
+++ media/base/audio_bus.h	(working copy)
@@ -45,6 +45,11 @@
   // Returns the required memory size to use the WrapMemory() method.
   static int CalculateMemorySize(const AudioParameters& params);
 
+  // Calculates the required size for an AudioBus with the given params, sets
+  // |aligned_frames| to the actual frame length of each channel array.
+  static int CalculateMemorySizeFromChannels(int channels, int frames,
+                                             int* aligned_frames);
+
   // Helper methods for converting an AudioBus from and to interleaved integer
   // data.  Expects interleaving to be [ch0, ch1, ..., chN, ch0, ch1, ...] with
   // |bytes_per_sample| per value.  Values are scaled and bias corrected during