Guard against uninitialized packetization modes.

webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc

 /*
  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 63 matching lines @@
     offset += kLengthFieldSize + nalu_size;
   }
   return true;
 }
 
 }  // namespace
 
 RtpPacketizerH264::RtpPacketizerH264(size_t max_payload_len,
                                      H264PacketizationMode packetization_mode)
     : max_payload_len_(max_payload_len),
-      packetization_mode_(packetization_mode) {}
+      packetization_mode_(packetization_mode) {
+  // Guard against uninitialized memory in packetization_mode.
+  RTC_CHECK(packetization_mode == H264PacketizationMode::NonInterleaved ||
+            packetization_mode == H264PacketizationMode::SingleNalUnit);
+}
 
 RtpPacketizerH264::~RtpPacketizerH264() {
 }
 
 RtpPacketizerH264::Fragment::Fragment(const uint8_t* buffer, size_t length)
     : buffer(buffer), length(length) {}
 RtpPacketizerH264::Fragment::Fragment(const Fragment& fragment)
     : buffer(fragment.buffer), length(fragment.length) {}
 
 void RtpPacketizerH264::SetPayloadData(
@@ skipping 520 matching lines @@
   h264->packetization_type = kH264FuA;
   h264->nalu_type = original_nal_type;
   if (first_fragment) {
     h264->nalus[h264->nalus_length] = nalu;
     h264->nalus_length = 1;
   }
   return true;
 }
 
 }  // namespace webrtc