Express audio delay more precisely in frames rather than milliseconds.

media/audio/audio_device_thread.h

Index: media/audio/audio_device_thread.h
diff --git a/media/audio/audio_device_thread.h b/media/audio/audio_device_thread.h
index 7ec9d6ea751da51a5919741d71bae378a272f65c..3cd673c4520bda7e0799be7337c6c4db4d7e67f6 100644
--- a/media/audio/audio_device_thread.h
+++ b/media/audio/audio_device_thread.h
@@ -60,8 +60,9 @@ class MEDIA_EXPORT AudioDeviceThread {
     // The variables are 'const' since values are calculated/set in the
     // constructor and must never change.
     const AudioParameters audio_parameters_;
-    const int samples_per_ms_;
-    const int bytes_per_ms_;
+    const double samples_per_ms_;
+    const double bytes_per_ms_;
+    const uint32_t bytes_per_frame_;
 
     base::SharedMemory shared_memory_;
     const int memory_length_;