[Cast] Fix log_deserializer BasePacketEvent merge bug.

media/cast/logging/log_deserializer.cc

 // Copyright 2014 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.
 
 #include "media/cast/logging/log_deserializer.h"
 
 #include <map>
 #include <utility>
 
 #include "base/big_endian.h"
@@ skipping 17 matching lines @@
 const int kMaxUncompressedBytes = 60 * 1000 * 1000;
 
 void MergePacketEvent(const AggregatedPacketEvent& from,
     linked_ptr<AggregatedPacketEvent> to) {
   for (int i = 0; i < from.base_packet_event_size(); i++) {
     const BasePacketEvent& from_base_event = from.base_packet_event(i);
     bool merged = false;
     for (int j = 0; j < to->base_packet_event_size(); j++) {
       BasePacketEvent* to_base_event = to->mutable_base_packet_event(j);
       if (from_base_event.packet_id() == to_base_event->packet_id()) {
+        int packet_size = std::max(
+            from_base_event.size(), to_base_event->size());
+        // Need special merge logic here because we need to prevent a valid
+        // packet size (> 0) from being overwritten with an invalid one (= 0).
         to_base_event->MergeFrom(from_base_event);
+        to_base_event->set_size(packet_size);
         merged = true;
         break;
       }
     }
     if (!merged) {
       BasePacketEvent* to_base_event = to->add_base_packet_event();
       to_base_event->CopyFrom(from_base_event);
     }
   }
 }
@@ skipping 189 matching lines @@
   } else {
     return DoDeserializeEvents(data, data_bytes, audio_log, video_log);
   }
 }
 
 DeserializedLog::DeserializedLog() {}
 DeserializedLog::~DeserializedLog() {}
 
 }  // namespace cast
 }  // namespace media