Fix "value possibly truncated" warnings on MSVC, net/spdy/ edition.

net/spdy/spdy_session.h

Index: net/spdy/spdy_session.h
diff --git a/net/spdy/spdy_session.h b/net/spdy/spdy_session.h
index 862918b00b49a0b9d582658fe9fcc93f94971b49..183a91fdd7b2730951d527375949b020a12b0c62 100644
--- a/net/spdy/spdy_session.h
+++ b/net/spdy/spdy_session.h
@@ -725,7 +725,7 @@ class NET_EXPORT SpdySession : public BufferedSpdyFramerVisitorInterface,
                              RequestPriority priority);
 
   // Send the PING frame.
-  void WritePingFrame(uint32 unique_id, bool is_ack);
+  void WritePingFrame(SpdyPingId unique_id, bool is_ack);
 
   // Post a CheckPingStatus call after delay. Don't post if there is already
   // CheckPingStatus running.
@@ -944,7 +944,7 @@ class NET_EXPORT SpdySession : public BufferedSpdyFramerVisitorInterface,
 
   int64 pings_in_flight() const { return pings_in_flight_; }
 
-  uint32 next_ping_id() const { return next_ping_id_; }
+  SpdyPingId next_ping_id() const { return next_ping_id_; }
 
   base::TimeTicks last_activity_time() const { return last_activity_time_; }
 
@@ -1081,7 +1081,7 @@ class NET_EXPORT SpdySession : public BufferedSpdyFramerVisitorInterface,
   int64 pings_in_flight_;
 
   // This is the next ping_id (unique_id) to be sent in PING frame.
-  uint32 next_ping_id_;
+  SpdyPingId next_ping_id_;
 
   // This is the last time we have sent a PING.
   base::TimeTicks last_ping_sent_time_;