diff --git a/media/BUILD.gn b/media/BUILD.gn
index f987fb3..88119e3 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -332,6 +332,31 @@
   }
 }
 
+# Heavy but optional helper for unittests and webrtc users who prefer to use
+# defaults factories or do not worry about extra dependencies and binary size.
+rtc_source_set("rtc_media_engine_defaults") {
+  visibility = [ "*" ]
+  allow_poison = [
+    "audio_codecs",
+    "software_video_codecs",
+  ]
+  sources = [
+    "engine/webrtc_media_engine_defaults.cc",
+    "engine/webrtc_media_engine_defaults.h",
+  ]
+  deps = [
+    ":rtc_audio_video",
+    "../api/audio_codecs:builtin_audio_decoder_factory",
+    "../api/audio_codecs:builtin_audio_encoder_factory",
+    "../api/task_queue:default_task_queue_factory",
+    "../api/video:builtin_video_bitrate_allocator_factory",
+    "../api/video_codecs:builtin_video_decoder_factory",
+    "../api/video_codecs:builtin_video_encoder_factory",
+    "../modules/audio_processing:api",
+    "../rtc_base:checks",
+  ]
+}
+
 rtc_static_library("rtc_data") {
   defines = []
   deps = [
@@ -472,6 +497,7 @@
       ":rtc_internal_video_codecs",
       ":rtc_media",
       ":rtc_media_base",
+      ":rtc_media_engine_defaults",
       ":rtc_media_tests_utils",
       ":rtc_simulcast_encoder_adapter",
       ":rtc_vp9_profile",
diff --git a/media/engine/webrtc_media_engine.cc b/media/engine/webrtc_media_engine.cc
index 48269ee..e2ead01 100644
--- a/media/engine/webrtc_media_engine.cc
+++ b/media/engine/webrtc_media_engine.cc
@@ -29,6 +29,26 @@
 
 namespace cricket {
 
+std::unique_ptr<MediaEngineInterface> CreateMediaEngine(
+    MediaEngineDependencies dependencies) {
+  auto audio_engine = absl::make_unique<WebRtcVoiceEngine>(
+      dependencies.task_queue_factory, std::move(dependencies.adm),
+      std::move(dependencies.audio_encoder_factory),
+      std::move(dependencies.audio_decoder_factory),
+      std::move(dependencies.audio_mixer),
+      std::move(dependencies.audio_processing));
+#ifdef HAVE_WEBRTC_VIDEO
+  auto video_engine = absl::make_unique<WebRtcVideoEngine>(
+      std::move(dependencies.video_encoder_factory),
+      std::move(dependencies.video_decoder_factory),
+      std::move(dependencies.video_bitrate_allocator_factory));
+#else
+  auto video_engine = absl::make_unique<NullWebRtcVideoEngine>();
+#endif
+  return absl::make_unique<CompositeMediaEngine>(std::move(audio_engine),
+                                                 std::move(video_engine));
+}
+
 std::unique_ptr<MediaEngineInterface> WebRtcMediaEngineFactory::Create(
     rtc::scoped_refptr<webrtc::AudioDeviceModule> adm,
     rtc::scoped_refptr<webrtc::AudioEncoderFactory> audio_encoder_factory,
diff --git a/media/engine/webrtc_media_engine.h b/media/engine/webrtc_media_engine.h
index 9a906fe..70f3ba3 100644
--- a/media/engine/webrtc_media_engine.h
+++ b/media/engine/webrtc_media_engine.h
@@ -15,6 +15,7 @@
 #include <string>
 #include <vector>
 
+#include "api/task_queue/task_queue_factory.h"
 #include "call/call.h"
 #include "media/base/media_engine.h"
 #include "modules/audio_device/include/audio_device.h"
@@ -30,6 +31,30 @@
 
 namespace cricket {
 
+struct MediaEngineDependencies {
+  MediaEngineDependencies() = default;
+  MediaEngineDependencies(const MediaEngineDependencies&) = delete;
+  MediaEngineDependencies(MediaEngineDependencies&&) = default;
+  MediaEngineDependencies& operator=(const MediaEngineDependencies&) = delete;
+  MediaEngineDependencies& operator=(MediaEngineDependencies&&) = default;
+  ~MediaEngineDependencies() = default;
+
+  webrtc::TaskQueueFactory* task_queue_factory = nullptr;
+  rtc::scoped_refptr<webrtc::AudioDeviceModule> adm;
+  rtc::scoped_refptr<webrtc::AudioEncoderFactory> audio_encoder_factory;
+  rtc::scoped_refptr<webrtc::AudioDecoderFactory> audio_decoder_factory;
+  rtc::scoped_refptr<webrtc::AudioMixer> audio_mixer;
+  rtc::scoped_refptr<webrtc::AudioProcessing> audio_processing;
+
+  std::unique_ptr<webrtc::VideoEncoderFactory> video_encoder_factory;
+  std::unique_ptr<webrtc::VideoDecoderFactory> video_decoder_factory;
+  std::unique_ptr<webrtc::VideoBitrateAllocatorFactory>
+      video_bitrate_allocator_factory;
+};
+
+std::unique_ptr<MediaEngineInterface> CreateMediaEngine(
+    MediaEngineDependencies dependencies);
+
 class WebRtcMediaEngineFactory {
  public:
   // These Create methods may be called on any thread, though the engine is
diff --git a/media/engine/webrtc_media_engine_defaults.cc b/media/engine/webrtc_media_engine_defaults.cc
new file mode 100644
index 0000000..038cd4e
--- /dev/null
+++ b/media/engine/webrtc_media_engine_defaults.cc
@@ -0,0 +1,47 @@
+/*
+ *  Copyright (c) 2019 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 "media/engine/webrtc_media_engine_defaults.h"
+
+#include "api/audio_codecs/builtin_audio_decoder_factory.h"
+#include "api/audio_codecs/builtin_audio_encoder_factory.h"
+#include "api/task_queue/default_task_queue_factory.h"
+#include "api/video/builtin_video_bitrate_allocator_factory.h"
+#include "api/video_codecs/builtin_video_decoder_factory.h"
+#include "api/video_codecs/builtin_video_encoder_factory.h"
+#include "modules/audio_processing/include/audio_processing.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+void SetMediaEngineDefaults(cricket::MediaEngineDependencies* deps) {
+  RTC_DCHECK(deps);
+  if (deps->task_queue_factory == nullptr) {
+    static TaskQueueFactory* const task_queue_factory =
+        CreateDefaultTaskQueueFactory().release();
+    deps->task_queue_factory = task_queue_factory;
+  }
+  if (deps->audio_encoder_factory == nullptr)
+    deps->audio_encoder_factory = CreateBuiltinAudioEncoderFactory();
+  if (deps->audio_decoder_factory == nullptr)
+    deps->audio_decoder_factory = CreateBuiltinAudioDecoderFactory();
+  if (deps->audio_processing == nullptr)
+    deps->audio_processing = AudioProcessingBuilder().Create();
+
+  if (deps->video_encoder_factory == nullptr)
+    deps->video_encoder_factory = CreateBuiltinVideoEncoderFactory();
+  if (deps->video_decoder_factory == nullptr)
+    deps->video_decoder_factory = CreateBuiltinVideoDecoderFactory();
+  if (deps->video_bitrate_allocator_factory == nullptr) {
+    deps->video_bitrate_allocator_factory =
+        CreateBuiltinVideoBitrateAllocatorFactory();
+  }
+}
+
+}  // namespace webrtc
diff --git a/media/engine/webrtc_media_engine_defaults.h b/media/engine/webrtc_media_engine_defaults.h
new file mode 100644
index 0000000..c61d069
--- /dev/null
+++ b/media/engine/webrtc_media_engine_defaults.h
@@ -0,0 +1,23 @@
+/*
+ *  Copyright (c) 2019 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 MEDIA_ENGINE_WEBRTC_MEDIA_ENGINE_DEFAULTS_H_
+#define MEDIA_ENGINE_WEBRTC_MEDIA_ENGINE_DEFAULTS_H_
+
+#include "media/engine/webrtc_media_engine.h"
+
+namespace webrtc {
+
+// Sets required but null dependencies with default factories.
+void SetMediaEngineDefaults(cricket::MediaEngineDependencies* deps);
+
+}  // namespace webrtc
+
+#endif  // MEDIA_ENGINE_WEBRTC_MEDIA_ENGINE_DEFAULTS_H_
diff --git a/media/engine/webrtc_media_engine_unittest.cc b/media/engine/webrtc_media_engine_unittest.cc
index 19542a9..722b227 100644
--- a/media/engine/webrtc_media_engine_unittest.cc
+++ b/media/engine/webrtc_media_engine_unittest.cc
@@ -9,6 +9,7 @@
  */
 
 #include <memory>
+#include <utility>
 
 #include "api/audio_codecs/builtin_audio_decoder_factory.h"
 #include "api/audio_codecs/builtin_audio_encoder_factory.h"
@@ -16,6 +17,7 @@
 #include "api/video_codecs/builtin_video_decoder_factory.h"
 #include "api/video_codecs/builtin_video_encoder_factory.h"
 #include "media/engine/webrtc_media_engine.h"
+#include "media/engine/webrtc_media_engine_defaults.h"
 #include "modules/audio_processing/include/audio_processing.h"
 #include "test/field_trial.h"
 #include "test/gtest.h"
@@ -306,4 +308,14 @@
   EXPECT_TRUE(engine);
 }
 
+TEST(WebRtcMediaEngineFactoryTest, Create) {
+  MediaEngineDependencies deps;
+  webrtc::SetMediaEngineDefaults(&deps);
+
+  std::unique_ptr<MediaEngineInterface> engine =
+      CreateMediaEngine(std::move(deps));
+
+  EXPECT_TRUE(engine);
+}
+
 }  // namespace cricket