diff --git a/modules/audio_device/ios/audio_device_unittest_ios.mm b/modules/audio_device/ios/audio_device_unittest_ios.mm
index 47b873d4a9..19ff9c9233 100644
--- a/modules/audio_device/ios/audio_device_unittest_ios.mm
+++ b/modules/audio_device/ios/audio_device_unittest_ios.mm
@@ -22,11 +22,11 @@
 #include "modules/audio_device/ios/audio_device_ios.h"
 #include "rtc_base/arraysize.h"
 #include "rtc_base/criticalsection.h"
+#include "rtc_base/event.h"
 #include "rtc_base/format_macros.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/scoped_ref_ptr.h"
 #include "rtc_base/timeutils.h"
-#include "system_wrappers/include/event_wrapper.h"
 #include "test/gmock.h"
 #include "test/gtest.h"
 #include "test/testsupport/fileutils.h"
@@ -372,7 +372,7 @@ class MockAudioTransportIOS : public test::MockAudioTransport {
 
   // Set default actions of the mock object. We are delegating to fake
   // implementations (of AudioStreamInterface) here.
-  void HandleCallbacks(EventWrapper* test_is_done,
+  void HandleCallbacks(rtc::Event* test_is_done,
                        AudioStreamInterface* audio_stream,
                        size_t num_callbacks) {
     test_is_done_ = test_is_done;
@@ -461,7 +461,7 @@ class MockAudioTransportIOS : public test::MockAudioTransport {
   bool rec_mode() const { return type_ & kRecording; }
 
  private:
-  EventWrapper* test_is_done_;
+  rtc::Event* test_is_done_;
   size_t num_callbacks_;
   int type_;
   size_t play_count_;
@@ -472,7 +472,7 @@ class MockAudioTransportIOS : public test::MockAudioTransport {
 // AudioDeviceTest test fixture.
 class AudioDeviceTest : public ::testing::Test {
  protected:
-  AudioDeviceTest() : test_is_done_(EventWrapper::Create()) {
+  AudioDeviceTest() {
     old_sev_ = rtc::LogMessage::GetLogToDebug();
     // Set suitable logging level here. Change to rtc::LS_INFO for more verbose
     // output. See webrtc/rtc_base/logging.h for complete list of options.
@@ -572,7 +572,7 @@ class AudioDeviceTest : public ::testing::Test {
     EXPECT_FALSE(audio_device()->Recording());
   }
 
-  std::unique_ptr<EventWrapper> test_is_done_;
+  rtc::Event test_is_done_;
   rtc::scoped_refptr<AudioDeviceModule> audio_device_;
   AudioParameters playout_parameters_;
   AudioParameters record_parameters_;
@@ -662,7 +662,7 @@ TEST_F(AudioDeviceTest, DISABLED_StartPlayoutOnTwoInstances) {
   // has been done successfully and that there is no conflict with the already
   // playing first ADM.
   MockAudioTransportIOS mock2(kPlayout);
-  mock2.HandleCallbacks(test_is_done_.get(), nullptr, kNumCallbacks);
+  mock2.HandleCallbacks(&test_is_done_, nullptr, kNumCallbacks);
   EXPECT_CALL(
       mock2, NeedMorePlayData(playout_frames_per_10ms_buffer(), kBytesPerSample,
                               playout_channels(), playout_sample_rate(),
@@ -671,7 +671,7 @@ TEST_F(AudioDeviceTest, DISABLED_StartPlayoutOnTwoInstances) {
   EXPECT_EQ(0, second_audio_device->RegisterAudioCallback(&mock2));
   EXPECT_EQ(0, second_audio_device->StartPlayout());
   EXPECT_TRUE(second_audio_device->Playing());
-  test_is_done_->Wait(kTestTimeOutInMilliseconds);
+  test_is_done_.Wait(kTestTimeOutInMilliseconds);
   EXPECT_EQ(0, second_audio_device->StopPlayout());
   EXPECT_FALSE(second_audio_device->Playing());
   EXPECT_FALSE(second_audio_device->PlayoutIsInitialized());
@@ -683,14 +683,14 @@ TEST_F(AudioDeviceTest, DISABLED_StartPlayoutOnTwoInstances) {
 // audio samples to play out using the NeedMorePlayData callback.
 TEST_F(AudioDeviceTest, StartPlayoutVerifyCallbacks) {
   MockAudioTransportIOS mock(kPlayout);
-  mock.HandleCallbacks(test_is_done_.get(), nullptr, kNumCallbacks);
+  mock.HandleCallbacks(&test_is_done_, nullptr, kNumCallbacks);
   EXPECT_CALL(mock, NeedMorePlayData(playout_frames_per_10ms_buffer(),
                                      kBytesPerSample, playout_channels(),
                                      playout_sample_rate(), NotNull(), _, _, _))
       .Times(AtLeast(kNumCallbacks));
   EXPECT_EQ(0, audio_device()->RegisterAudioCallback(&mock));
   StartPlayout();
-  test_is_done_->Wait(kTestTimeOutInMilliseconds);
+  test_is_done_.Wait(kTestTimeOutInMilliseconds);
   StopPlayout();
 }
 
@@ -698,7 +698,7 @@ TEST_F(AudioDeviceTest, StartPlayoutVerifyCallbacks) {
 // audio samples via the RecordedDataIsAvailable callback.
 TEST_F(AudioDeviceTest, StartRecordingVerifyCallbacks) {
   MockAudioTransportIOS mock(kRecording);
-  mock.HandleCallbacks(test_is_done_.get(), nullptr, kNumCallbacks);
+  mock.HandleCallbacks(&test_is_done_, nullptr, kNumCallbacks);
   EXPECT_CALL(mock,
               RecordedDataIsAvailable(
                   NotNull(), record_frames_per_10ms_buffer(), kBytesPerSample,
@@ -708,7 +708,7 @@ TEST_F(AudioDeviceTest, StartRecordingVerifyCallbacks) {
 
   EXPECT_EQ(0, audio_device()->RegisterAudioCallback(&mock));
   StartRecording();
-  test_is_done_->Wait(kTestTimeOutInMilliseconds);
+  test_is_done_.Wait(kTestTimeOutInMilliseconds);
   StopRecording();
 }
 
@@ -716,7 +716,7 @@ TEST_F(AudioDeviceTest, StartRecordingVerifyCallbacks) {
 // active in both directions.
 TEST_F(AudioDeviceTest, StartPlayoutAndRecordingVerifyCallbacks) {
   MockAudioTransportIOS mock(kPlayout | kRecording);
-  mock.HandleCallbacks(test_is_done_.get(), nullptr, kNumCallbacks);
+  mock.HandleCallbacks(&test_is_done_, nullptr, kNumCallbacks);
   EXPECT_CALL(mock, NeedMorePlayData(playout_frames_per_10ms_buffer(),
                                      kBytesPerSample, playout_channels(),
                                      playout_sample_rate(), NotNull(), _, _, _))
@@ -730,7 +730,7 @@ TEST_F(AudioDeviceTest, StartPlayoutAndRecordingVerifyCallbacks) {
   EXPECT_EQ(0, audio_device()->RegisterAudioCallback(&mock));
   StartPlayout();
   StartRecording();
-  test_is_done_->Wait(kTestTimeOutInMilliseconds);
+  test_is_done_.Wait(kTestTimeOutInMilliseconds);
   StopRecording();
   StopPlayout();
 }
@@ -746,12 +746,11 @@ TEST_F(AudioDeviceTest, RunPlayoutWithFileAsSource) {
   std::string file_name = GetFileName(playout_sample_rate());
   std::unique_ptr<FileAudioStream> file_audio_stream(
       new FileAudioStream(num_callbacks, file_name, playout_sample_rate()));
-  mock.HandleCallbacks(test_is_done_.get(), file_audio_stream.get(),
-                       num_callbacks);
+  mock.HandleCallbacks(&test_is_done_, file_audio_stream.get(), num_callbacks);
   // SetMaxPlayoutVolume();
   EXPECT_EQ(0, audio_device()->RegisterAudioCallback(&mock));
   StartPlayout();
-  test_is_done_->Wait(kTestTimeOutInMilliseconds);
+  test_is_done_.Wait(kTestTimeOutInMilliseconds);
   StopPlayout();
 }
 
@@ -780,14 +779,13 @@ TEST_F(AudioDeviceTest, RunPlayoutAndRecordingInFullDuplex) {
   NiceMock<MockAudioTransportIOS> mock(kPlayout | kRecording);
   std::unique_ptr<FifoAudioStream> fifo_audio_stream(
       new FifoAudioStream(playout_frames_per_10ms_buffer()));
-  mock.HandleCallbacks(test_is_done_.get(), fifo_audio_stream.get(),
-                       kFullDuplexTimeInSec * kNumCallbacksPerSecond);
+  mock.HandleCallbacks(
+      &test_is_done_, fifo_audio_stream.get(), kFullDuplexTimeInSec * kNumCallbacksPerSecond);
   // SetMaxPlayoutVolume();
   EXPECT_EQ(0, audio_device()->RegisterAudioCallback(&mock));
   StartRecording();
   StartPlayout();
-  test_is_done_->Wait(
-      std::max(kTestTimeOutInMilliseconds, 1000 * kFullDuplexTimeInSec));
+  test_is_done_.Wait(std::max(kTestTimeOutInMilliseconds, 1000 * kFullDuplexTimeInSec));
   StopPlayout();
   StopRecording();
   EXPECT_LE(fifo_audio_stream->average_size(), 10u);
@@ -809,15 +807,15 @@ TEST_F(AudioDeviceTest, DISABLED_MeasureLoopbackLatency) {
   NiceMock<MockAudioTransportIOS> mock(kPlayout | kRecording);
   std::unique_ptr<LatencyMeasuringAudioStream> latency_audio_stream(
       new LatencyMeasuringAudioStream(playout_frames_per_10ms_buffer()));
-  mock.HandleCallbacks(test_is_done_.get(), latency_audio_stream.get(),
+  mock.HandleCallbacks(&test_is_done_,
+                       latency_audio_stream.get(),
                        kMeasureLatencyTimeInSec * kNumCallbacksPerSecond);
   EXPECT_EQ(0, audio_device()->RegisterAudioCallback(&mock));
   // SetMaxPlayoutVolume();
   // DisableBuiltInAECIfAvailable();
   StartRecording();
   StartPlayout();
-  test_is_done_->Wait(
-      std::max(kTestTimeOutInMilliseconds, 1000 * kMeasureLatencyTimeInSec));
+  test_is_done_.Wait(std::max(kTestTimeOutInMilliseconds, 1000 * kMeasureLatencyTimeInSec));
   StopPlayout();
   StopRecording();
   // Verify that the correct number of transmitted impulses are detected.