Avoid undefined behavior in vp8 screenshare_layers

webrtc/modules/video_coding/codecs/vp8/screenshare_layers_unittest.cc

 /*
  *  Copyright (c) 2013 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.
  */
 
+#include <vector>
+
 #include "gtest/gtest.h"
 #include "vpx/vpx_encoder.h"
 #include "vpx/vp8cx.h"
 #include "webrtc/base/scoped_ptr.h"
 #include "webrtc/modules/video_coding/include/video_codec_interface.h"
 #include "webrtc/modules/video_coding/codecs/vp8/screenshare_layers.h"
 #include "webrtc/modules/video_coding/utility/mock/mock_frame_dropper.h"
 
 using ::testing::_;
 using ::testing::NiceMock;
@@ skipping 13 matching lines @@
 class ScreenshareLayerTest : public ::testing::Test {
  protected:
   ScreenshareLayerTest() : min_qp_(2), max_qp_(kDefaultQp), frame_size_(-1) {}
   virtual ~ScreenshareLayerTest() {}
 
   void EncodeFrame(uint32_t timestamp,
                    bool base_sync,
                    CodecSpecificInfoVP8* vp8_info,
                    int* flags) {
     *flags = layers_->EncodeFlags(timestamp);
+    if (*flags == -1)
+      return;
     layers_->PopulateCodecSpecific(base_sync, vp8_info, timestamp);
     ASSERT_NE(-1, frame_size_);
     layers_->FrameEncoded(frame_size_, timestamp, kDefaultQp);
   }
 
   void ConfigureBitrates() {
     vpx_codec_enc_cfg_t vpx_cfg;
     memset(&vpx_cfg, 0, sizeof(vpx_codec_enc_cfg_t));
     vpx_cfg.rc_min_quantizer = min_qp_;
     vpx_cfg.rc_max_quantizer = max_qp_;
@@ skipping 382 matching lines @@
 
   layers_->EncodeFlags(timestamp);
   timestamp += kTimestampDelta5Fps;
   EXPECT_TRUE(layers_->UpdateConfiguration(&cfg));
   layers_->PopulateCodecSpecific(false, &vp8_info, timestamp);
   EXPECT_EQ(cfg.rc_max_quantizer, static_cast<unsigned int>(kDefaultQp));
   layers_->FrameEncoded(frame_size_, timestamp, kDefaultQp);
 }
 
 }  // namespace webrtc