Prevent depacketizer OOB reads on zero-length VP8 payload.

webrtc/modules/rtp_rtcp/source/rtp_format_vp8_unittest.cc

 /*
  *  Copyright (c) 2012 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 578 matching lines @@
   EXPECT_EQ(kRtpVideoVp8, payload.type.Video.codec);
   VerifyBasicHeader(&payload.type, 1, 1, 0);
   VerifyExtensions(&payload.type,
                    input_header.pictureId,
                    input_header.tl0PicIdx,
                    input_header.temporalIdx,
                    input_header.keyIdx);
   EXPECT_EQ(payload.type.Video.codecHeader.VP8.layerSync,
             input_header.layerSync);
 }
+
+TEST_F(RtpDepacketizerVp8Test, TestEmptyPayload) {
+  // Using a wild pointer to crash on accesses from inside the depacketizer.
+  uint8_t* garbage_ptr = reinterpret_cast<uint8_t*>(0x4711);
+  RtpDepacketizer::ParsedPayload payload;
+  EXPECT_FALSE(depacketizer_->Parse(&payload, garbage_ptr, 0));
+}
 }  // namespace webrtc