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

media/cast/net/rtp/frame_buffer.h

Index: media/cast/net/rtp/frame_buffer.h
diff --git a/media/cast/net/rtp/frame_buffer.h b/media/cast/net/rtp/frame_buffer.h
index dedd82e0aac683561c7ce88fde78f70e901e8df9..2f5fd1718ec8f5a21ad8b2224bef8621158854db 100644
--- a/media/cast/net/rtp/frame_buffer.h
+++ b/media/cast/net/rtp/frame_buffer.h
@@ -8,6 +8,7 @@
 #include <map>
 #include <vector>
 
+#include "media/cast/common/rtp_time.h"
 #include "media/cast/net/cast_transport_config.h"
 #include "media/cast/net/rtp/rtp_defines.h"
 
@@ -46,7 +47,7 @@ class FrameBuffer {
   bool is_key_frame_;
   size_t total_data_size_;
   uint32 last_referenced_frame_id_;
-  uint32 rtp_timestamp_;
+  RtpTimeTicks rtp_timestamp_;
   PacketMap packets_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameBuffer);