Adds shared base class for data units.

This reduces code duplication and ensures common behavior
between the unit classes.

Bug: webrtc:9709
Change-Id: I9529ef10b3f538355f53250a2b67c6b4e250cce8
Reviewed-on: https://webrtc-review.googlesource.com/c/110901
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25690}
diff --git a/api/DEPS b/api/DEPS
index a68d704..b22f58f 100644
--- a/api/DEPS
+++ b/api/DEPS
@@ -43,6 +43,7 @@
   ".*\.h": [
     "+rtc_base/checks.h",
     "+rtc_base/system/rtc_export.h",
+    "+rtc_base/units/unit_base.h",
   ],
 
   "array_view\.h": [
@@ -252,22 +253,6 @@
     "+modules/video_coding/include/video_codec_interface.h"
   ],
 
-  "data_rate\.h": [
-    "+rtc_base/numerics/safe_conversions.h",
-  ],
-
-  "data_size\.h": [
-    "+rtc_base/numerics/safe_conversions.h",
-  ],
-
-  "time_delta\.h": [
-    "+rtc_base/numerics/safe_conversions.h",
-  ],
-
-  "timestamp\.h": [
-    "+rtc_base/numerics/safe_conversions.h",
-  ],
-
   "i010_buffer\.h": [
     "+rtc_base/memory/aligned_malloc.h"
   ],