[GCM] Add TTL support

google_apis/gcm/base/mcs_util.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Utility methods for MCS interactions.
 
 #ifndef GOOGLE_APIS_GCM_BASE_MCS_UTIL_H_
 #define GOOGLE_APIS_GCM_BASE_MCS_UTIL_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "google_apis/gcm/base/gcm_export.h"
 #include "google_apis/gcm/protocol/mcs.pb.h"
 
+namespace base {
+class Clock;
+}
+
 namespace net {
 class StreamSocket;
 }
 
 namespace gcm {
 
 // MCS Message tags.
 // WARNING: the order of these tags must remain the same, as the tag values
 // must be consistent with those used on the server.
 enum MCSProtoTag {
@@ skipping 41 matching lines @@
     const google::protobuf::MessageLite& message);
 GCM_EXPORT void SetPersistentId(
     const std::string& persistent_id,
     google::protobuf::MessageLite* message);
 GCM_EXPORT uint32 GetLastStreamIdReceived(
     const google::protobuf::MessageLite& protobuf);
 GCM_EXPORT void SetLastStreamIdReceived(
     uint32 last_stream_id_received,
     google::protobuf::MessageLite* protobuf);
 
+// Returns whether the TTL (time to live) for this message has expired, based
+// on the |sent| timestamps and base::TimeTicks::Now(). If |protobuf| is not
+// for a DataMessageStanza or the TTL is 0, will return false.
+GCM_EXPORT bool HasTTLExpired(const google::protobuf::MessageLite& protobuf,
+                              base::Clock* clock);
+GCM_EXPORT int GetTTL(const google::protobuf::MessageLite& protobuf);
+
 }  // namespace gcm
 
 #endif  // GOOGLE_APIS_GCM_BASE_MCS_UTIL_H_