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

chrome/common/cast_messages.h

Index: chrome/common/cast_messages.h
diff --git a/chrome/common/cast_messages.h b/chrome/common/cast_messages.h
index e10717189ffb17db6e5995c88eaab3e9ced5e578..35f985433c7fa15f2231ac750508d3d739587b94 100644
--- a/chrome/common/cast_messages.h
+++ b/chrome/common/cast_messages.h
@@ -3,15 +3,52 @@
 // found in the LICENSE file.
 
 // IPC messages for the Cast transport API.
-// Multiply-included message file, hence no include guard.
 
 #include "ipc/ipc_message_macros.h"
 #include "media/cast/cast_sender.h"
+#include "media/cast/common/rtp_time.h"
 #include "media/cast/logging/logging_defines.h"
 #include "media/cast/net/cast_transport_sender.h"
 #include "media/cast/net/rtcp/rtcp_defines.h"
 #include "net/base/ip_endpoint.h"
 
+#ifndef CHROME_COMMON_CAST_MESSAGES_H_
+#define CHROME_COMMON_CAST_MESSAGES_H_
+
+namespace IPC {
+
+template<>
+struct ParamTraits<media::cast::RtpTimeTicks> {

[Mike West, 2015/12/10 08:54:46]

Please don't inline the definitions of these methods. Sticking them into a new
`case_messages.cc` would be preferable.

[miu, 2015/12/11 23:00:28]

Done.

+  using param_type = media::cast::RtpTimeTicks;
+
+  static void Write(Message* m, const param_type& p) {
+    auto serialized = p.SerializeForIPC();

[Mike West, 2015/12/10 08:54:46]

Why `auto` and not `uint64_t`? I'd prefer clarity. Being explicit about the type
also allows you to avoid the strange construction on line #31.

[miu, 2015/12/11 23:00:28]

Done.  I was originally flip-flopping between representations while I was
authoring this change.  I'll just use uint64_t here.

+    ParamTraits<decltype(serialized)>::Write(m, serialized);
+  }
+
+  static bool Read(const Message* m, base::PickleIterator* iter,
+                   param_type* r) {
+    decltype(r->SerializeForIPC()) serialized;
+    if (ParamTraits<decltype(serialized)>::Read(m, iter, &serialized)) {
+      *r = param_type::DeserializeForIPC(serialized);
+      return true;
+    }
+    return false;
+  }
+
+  static void Log(const param_type& p, std::string* l) {
+    std::ostringstream oss;
+    oss << p;
+    l->append(oss.str());
+  }
+};
+
+}  // namespace IPC
+
+#endif  // CHROME_COMMON_CAST_MESSAGES_H_
+
+// Multiply-included message file, hence no include guard from here.
+
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_START CastMsgStart
@@ -161,7 +198,7 @@ IPC_MESSAGE_CONTROL4(
     int32 /* channel_id */,
     uint32 /* ssrc */,
     base::TimeTicks /* current_time */,
-    uint32 /* current_time_as_rtp_timestamp */)
+    media::cast::RtpTimeTicks /* current_time_as_rtp_timestamp */)
 
 IPC_MESSAGE_CONTROL3(
     CastHostMsg_CancelSendingFrames,