Add some comments for the entropy decoder.
Most of these comments were based on private email communication from
Timothy B. Terriberry <tterriberry@mozilla.com>.
Change-Id: I997833c0c032d58c7a44e63175531507e473cebf
diff --git a/aom_dsp/entcode.h b/aom_dsp/entcode.h
index 7ba2b1c..7518879 100644
--- a/aom_dsp/entcode.h
+++ b/aom_dsp/entcode.h
@@ -24,6 +24,7 @@
on a larger type, you can speed up the decoder by using it here.*/
typedef uint32_t od_ec_window;
+/*The size in bits of od_ec_window.*/
#define OD_EC_WINDOW_SIZE ((int)sizeof(od_ec_window) * CHAR_BIT)
/*The resolution of fractional-precision bit usage measurements, i.e.,
