Added a bitexactness test for the level estimator in the audio processing module

webrtc/modules/audio_processing/test/bitexactness_tools.h

 /*
  *  Copyright (c) 2016 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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_TEST_BITEXACTNESS_TOOLS_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_TEST_BITEXACTNESS_TOOLS_H_
 
 #include <vector>
 
 #include "webrtc/base/array_view.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace webrtc {
 namespace test {
 
+// Gtest PRED_FORMAT test function that compares two integers
+// and reports any differences.
+::testing::AssertionResult AssertIntegersNotEqual(const char* m_expr,
+                                                  const char* n_expr,
+                                                  const int& output,
+                                                  const int& reference);
+
 // Gtest PRED_FORMAT test function that compares two floats
 // and reports any differences.
 ::testing::AssertionResult AssertFloatsNotEqual(const char* m_expr,
                                                 const char* n_expr,
                                                 const float& output,
                                                 const float& reference);
 
 // Gtest EXPECT_PRED_FORMAT test function that compares two array views
 // and reports any differences.
 ::testing::AssertionResult AssertVectorsNotEqual(
     const char* m_expr,
     const char* n_expr,
     const rtc::ArrayView<const float>& output,
     const rtc::ArrayView<const float>& reference);
 
 }  // namespace test
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_TEST_BITEXACTNESS_TOOLS_H_