Adding second layer of the echo canceller 3 functionality.

webrtc/modules/audio_processing/aec3/echo_path_delay_estimator_unittest.cc

+/*
+ *  Copyright (c) 2017 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 "webrtc/modules/audio_processing/aec3/echo_path_delay_estimator.h"
+
+#include <sstream>
+#include <string>
+
+#include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
+#include "webrtc/modules/audio_processing/logging/apm_data_dumper.h"
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+namespace {
+
+std::string ProduceDebugText(int sample_rate_hz) {
+  std::ostringstream ss;
+  ss << "Sample rate: " << sample_rate_hz;
+  return ss.str();
+}
+
+}  // namespace
+
+// Verifies that the basic API calls work.
+TEST(EchoPathDelayEstimator, BasicApiCalls) {
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    ProduceDebugText(rate);
+    ApmDataDumper data_dumper(0);
+    EchoPathDelayEstimator estimator(&data_dumper, rate);
+    std::vector<float> render(std::vector<float>(kBlockSize, 0.f));
+    std::vector<float> capture(std::vector<float>(kBlockSize, 0.f));

[aleloi, 2017/01/20 14:45:37]

I think there is an extra copy constructor call here. Would 
  
  std::vector<float> render(kBlockSize, 0.f);

work?

[peah-webrtc, 2017/01/23 14:16:40]

Done.

+    for (size_t k = 0; k < 100; ++k) {
+      estimator.EstimateDelay(render, capture);
+    }
+  }
+}
+
+#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
+
+// Verifies the check for correct sample rate.
+TEST(EchoPathDelayEstimator, WrongSampleRate) {
+  ApmDataDumper data_dumper(0);
+  EXPECT_DEATH(EchoPathDelayEstimator remover(&data_dumper, 8001), "");
+}
+
+// Verifies the check for the render blocksize.
+TEST(EchoPathDelayEstimator, WrongRenderBlockSize) {
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    ProduceDebugText(rate);
+    ApmDataDumper data_dumper(0);
+    EchoPathDelayEstimator estimator(&data_dumper, rate);
+    std::vector<float> render(std::vector<float>(kBlockSize - 1, 0.f));

[aleloi, 2017/01/20 14:45:37]

Same here.

[peah-webrtc, 2017/01/23 14:16:40]

Done.

+    std::vector<float> capture(std::vector<float>(kBlockSize, 0.f));
+    EXPECT_DEATH(estimator.EstimateDelay(render, capture), "");
+  }
+}
+
+// Verifies the check for the capture blocksize.
+TEST(EchoPathDelayEstimator, WrongCaptureBlockSize) {
+  for (auto rate : {8000, 16000, 32000, 48000}) {
+    ProduceDebugText(rate);
+    ApmDataDumper data_dumper(0);
+    EchoPathDelayEstimator estimator(&data_dumper, rate);
+    std::vector<float> render(std::vector<float>(kBlockSize, 0.f));

[aleloi, 2017/01/20 14:45:37]

And here.

[peah-webrtc, 2017/01/23 14:16:40]

Done.

+    std::vector<float> capture(std::vector<float>(kBlockSize - 1, 0.f));
+    EXPECT_DEATH(estimator.EstimateDelay(render, capture), "");
+  }
+}
+
+// Verifies the check for non-null data dumper.
+TEST(EchoPathDelayEstimator, NullDataDumper) {
+  EXPECT_DEATH(EchoPathDelayEstimator(nullptr, 8000), "");
+}
+
+#endif
+
+}  // namespace webrtc