Add AudioRecord timestamps

Bug: 13569372
Bug: 22886739
Change-Id: I695b8a31fa427c6016f4170c09329859a41f19d2
diff --git a/hal/audio_hw.h b/hal/audio_hw.h
index 9565b74..be468fe 100644
--- a/hal/audio_hw.h
+++ b/hal/audio_hw.h
@@ -215,6 +215,7 @@
     bool enable_aec;
     bool enable_ns;
     audio_format_t format;
+    int64_t frames_read; /* total frames read, not cleared when entering standby */
 
     struct audio_device *dev;
 };