Replace uses of raw uint32's with a type-checked RtpTimeTicks data type.

media/cast/BUILD.gn

Index: media/cast/BUILD.gn
diff --git a/media/cast/BUILD.gn b/media/cast/BUILD.gn
index 51d9783d4fc6dbd15a6e28d94a485d6289a75643..086e284cd946286fb13d896cea54c7c6a278d7d6 100644
--- a/media/cast/BUILD.gn
+++ b/media/cast/BUILD.gn
@@ -24,6 +24,9 @@ source_set("common") {
     "cast_environment.h",
     "common/clock_drift_smoother.cc",
     "common/clock_drift_smoother.h",
+    "common/expanded_value_base.h",
+    "common/rtp_time.cc",
+    "common/rtp_time.h",
     "common/transport_encryption_handler.cc",
     "common/transport_encryption_handler.h",
     "constants.h",
@@ -101,6 +104,10 @@ source_set("net") {
   deps = [
     ":common",
   ]
+
+  public_deps = [
+    ":common",
+  ]
 }
 
 source_set("sender") {
@@ -301,6 +308,8 @@ group("cast_unittests_run") {
 
 test("cast_unittests") {
   sources = [
+    "common/expanded_value_base_unittest.cc",
+    "common/rtp_time_unittest.cc",
     "logging/encoding_event_subscriber_unittest.cc",
     "logging/receiver_time_offset_estimator_impl_unittest.cc",
     "logging/serialize_deserialize_test.cc",