Reland of land "media: Refactor MojoMediaClient" with fix. (patchset #2 id:260001 of https://codereview.chromium.org/1702453002/ )

Reason for revert:
Unrelated to https://crbug.com/586902. Relanding.

Original issue's description:
> Revert of Reland "media: Refactor MojoMediaClient" with fix. (patchset #2 id:20001 of https://codereview.chromium.org/1690213002/ )
>
> Reason for revert:
> Suspected to break a layout test on android.
> https://crbug.com/586902
>
> Original issue's description:
> > Reland "media: Refactor MojoMediaClient" with fix.
> >
> > This reverts commit 29775799918ebeb0f2aedd554722e3db0c6211c2.
> >
> > Instead of specifying a platform based MojoMediaClient at compile time,
> > provide the capability of setting one at run time. This improves the flexibility
> > of using MojoMediaApplication in different cases. For example, on desktop, we
> > may want to run the MojoMediaApplication in the utility process (for the CDM
> > service) and in the GPU process (for hardware decoding). In those two cases,
> > we'll want to specify two different MojoMediaClients even though we are on the
> > same platform.
> >
> > TBR=alokp@chromium.org
> > BUG=570357,571155
>
> TBR=alokp@chromium.org,jam@chromium.org,thakis@chromium.org,xhwang@chromium.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG=586902,570357,571155

TBR=alokp@chromium.org,jam@chromium.org,thakis@chromium.org,xhwang@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=586902,570357,571155

Review URL: https://codereview.chromium.org/1697233002

Cr-Commit-Position: refs/heads/master@{#375491}

17 files changed, 254 insertions, 139 deletions

diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index cd5004b..b6d2903 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -958,8 +958,10 @@ source_set("browser") {
     deps += [ "//chrome/browser/media/router" ]
   }
 
-  if (enable_mojo_media != "none") {
-    deps += [ "//media/mojo/services:default_application" ]
+  if (enable_mojo_media == "browser") {
+    deps += [ "//media/mojo/services:application" ]
+  } else if (enable_mojo_media != "none") {
+    configs += [ "//media/mojo/services:enable_mojo_media_config" ]
   }
 
   if (enable_wayland_server) {
diff --git a/chromecast/browser/cast_content_browser_client.cc b/chromecast/browser/cast_content_browser_client.cc
index aea55a6..12a4754 100644
--- a/chromecast/browser/cast_content_browser_client.cc
+++ b/chromecast/browser/cast_content_browser_client.cc
@@ -52,6 +52,7 @@
 #include "ui/gl/gl_switches.h"
 
 #if defined(ENABLE_MOJO_MEDIA_IN_BROWSER_PROCESS)
+#include "chromecast/media/mojo/cast_mojo_media_client.h"
 // nogncheck because of conditional dependency.
 #include "media/mojo/services/mojo_media_application.h"  // nogncheck
 #endif  // ENABLE_MOJO_MEDIA_IN_BROWSER_PROCESS
@@ -357,9 +358,10 @@ bool CastContentBrowserClient::CanCreateWindow(
 void CastContentBrowserClient::RegisterInProcessMojoApplications(
     StaticMojoApplicationMap* apps) {
 #if defined(ENABLE_MOJO_MEDIA_IN_BROWSER_PROCESS)
-  apps->insert(
-      std::make_pair(GURL("mojo:media"),
-                     base::Bind(::media::MojoMediaApplication::CreateApp)));
+  apps->insert(std::make_pair(
+      GURL("mojo:media"),
+      base::Bind(::media::MojoMediaApplication::CreateAppWithClient,
+                 base::Bind(&media::CastMojoMediaClient::Create))));
 #endif
 }
 
diff --git a/chromecast/media/mojo/BUILD.gn b/chromecast/media/mojo/BUILD.gn
index f197973..f8e8ec1 100644
--- a/chromecast/media/mojo/BUILD.gn
+++ b/chromecast/media/mojo/BUILD.gn
@@ -10,6 +10,7 @@ assert(enable_mojo_media == "browser")
 source_set("mojo") {
   sources = [
     "cast_mojo_media_client.cc",
+    "cast_mojo_media_client.h",
   ]
 
   public_deps = [
diff --git a/chromecast/media/mojo/cast_mojo_media_client.cc b/chromecast/media/mojo/cast_mojo_media_client.cc
index e239269..3a16021 100644
--- a/chromecast/media/mojo/cast_mojo_media_client.cc
+++ b/chromecast/media/mojo/cast_mojo_media_client.cc
@@ -2,31 +2,26 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "media/mojo/services/mojo_media_application.h"
+#include "chromecast/media/mojo/cast_mojo_media_client.h"
 
-#include "media/mojo/services/mojo_media_client.h"
-
-namespace {
-class CastMojoMediaClient : public ::media::MojoMediaClient {
- public:
-  CastMojoMediaClient() {}
-  ~CastMojoMediaClient() override {}
+namespace chromecast {
+namespace media {
 
-  // MojoMediaClient overrides.
-  void Initialize() override {}
-  scoped_ptr<::media::RendererFactory> CreateRendererFactory(
-      const scoped_refptr<::media::MediaLog>& media_log) override {
-    return scoped_ptr<::media::RendererFactory>();
-  }
+CastMojoMediaClient::CastMojoMediaClient() {}
 
- private:
-  DISALLOW_COPY_AND_ASSIGN(CastMojoMediaClient);
-};
-}  // namespace
+CastMojoMediaClient::~CastMojoMediaClient() {}
 
-namespace media {
 // static
-scoped_ptr<MojoMediaClient> MojoMediaClient::Create() {
-  return make_scoped_ptr(new CastMojoMediaClient());
+scoped_ptr<::media::MojoMediaClient> CastMojoMediaClient::Create() {
+  return scoped_ptr<::media::MojoMediaClient>(new CastMojoMediaClient());
 }
+
+void CastMojoMediaClient::Initialize() {}
+
+scoped_ptr<::media::RendererFactory> CastMojoMediaClient::CreateRendererFactory(
+    const scoped_refptr<::media::MediaLog>& /* media_log */) {
+  return scoped_ptr<::media::RendererFactory>();
+}
+
 }  // namespace media
+}  // namespace chromecast
diff --git a/chromecast/media/mojo/cast_mojo_media_client.h b/chromecast/media/mojo/cast_mojo_media_client.h
new file mode 100644
index 0000000..1f7fcde
--- /dev/null
+++ b/chromecast/media/mojo/cast_mojo_media_client.h
@@ -0,0 +1,32 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROMECAST_MEDIA_MOJO_CAST_MOJO_MEDIA_CLIENT_H_
+#define CHROMECAST_MEDIA_MOJO_CAST_MOJO_MEDIA_CLIENT_H_
+
+#include "media/mojo/services/mojo_media_client.h"
+
+namespace chromecast {
+namespace media {
+
+class CastMojoMediaClient : public ::media::MojoMediaClient {
+ public:
+  CastMojoMediaClient();
+  ~CastMojoMediaClient() override;
+
+  static scoped_ptr<::media::MojoMediaClient> Create();
+
+  // MojoMediaClient overrides.
+  void Initialize() override;
+  scoped_ptr<::media::RendererFactory> CreateRendererFactory(
+      const scoped_refptr<::media::MediaLog>& media_log) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CastMojoMediaClient);
+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_MOJO_CAST_MOJO_MEDIA_CLIENT_H_
diff --git a/content/shell/BUILD.gn b/content/shell/BUILD.gn
index e18c0b9..4847abd 100644
--- a/content/shell/BUILD.gn
+++ b/content/shell/BUILD.gn
@@ -245,8 +245,8 @@ static_library("content_shell_lib") {
       "//ppapi:blink_test_plugin",
     ]
   }
-  if (enable_mojo_media != "none") {
-    deps += [ "//media/mojo/services:default_application" ]
+  if (enable_mojo_media == "browser") {
+    deps += [ "//media/mojo/services:application" ]
   }
 
   if (is_win) {
diff --git a/media/mojo/services/BUILD.gn b/media/mojo/services/BUILD.gn
index 2292580..39384c9 100644
--- a/media/mojo/services/BUILD.gn
+++ b/media/mojo/services/BUILD.gn
@@ -150,30 +150,24 @@ source_set("application") {
     "service_factory_impl.h",
   ]
 
-  public_configs = [ ":enable_mojo_media_config" ]
-
-  deps = [
-    ":cdm_service",
-    ":renderer_service",
-    "//mojo/shell/public/cpp",
-  ]
-}
-
-source_set("default_application") {
   if (is_android) {
-    sources = [
+    sources += [
       "android_mojo_media_client.cc",
+      "android_mojo_media_client.h",
     ]
   } else {
-    sources = [
+    sources += [
       "default_mojo_media_client.cc",
+      "default_mojo_media_client.h",
     ]
   }
 
   public_configs = [ ":enable_mojo_media_config" ]
 
   deps = [
-    ":application",
+    ":cdm_service",
+    ":renderer_service",
+    "//mojo/shell/public/cpp",
   ]
 }
 
@@ -203,7 +197,7 @@ mojo_native_application("media") {
   ]
 
   deps = [
-    ":default_application",
+    ":application",
     "//mojo/logging",
     "//mojo/public/c/system:for_shared_library",
   ]
@@ -232,7 +226,9 @@ mojo_native_application("media_apptests") {
     "//testing/gtest",
   ]
 
-  data_deps = [ ":media" ]
+  data_deps = [
+    ":media",
+  ]
 }
 
 mojo_native_application("media_pipeline_integration_apptests") {
@@ -242,7 +238,9 @@ mojo_native_application("media_pipeline_integration_apptests") {
     "//media/test:mojo_pipeline_integration_tests",
   ]
 
-  data_deps = [ ":media" ]
+  data_deps = [
+    ":media",
+  ]
 }
 
 group("services") {
diff --git a/media/mojo/services/android_mojo_media_client.cc b/media/mojo/services/android_mojo_media_client.cc
index efd25c2..a7c270f 100644
--- a/media/mojo/services/android_mojo_media_client.cc
+++ b/media/mojo/services/android_mojo_media_client.cc
@@ -2,13 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "media/mojo/services/mojo_media_client.h"
+#include "media/mojo/services/android_mojo_media_client.h"
 
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 #include "media/base/android/android_cdm_factory.h"
-#include "media/base/bind_to_current_loop.h"
-#include "media/base/media.h"
 #include "media/mojo/interfaces/provision_fetcher.mojom.h"
 #include "media/mojo/services/mojo_provision_fetcher.h"
 #include "mojo/shell/public/cpp/connect.h"
@@ -16,6 +12,7 @@
 namespace media {
 
 namespace {
+
 scoped_ptr<ProvisionFetcher> CreateProvisionFetcher(
     mojo::shell::mojom::InterfaceProvider* service_provider) {
   interfaces::ProvisionFetcherPtr provision_fetcher_ptr;
@@ -24,24 +21,17 @@ scoped_ptr<ProvisionFetcher> CreateProvisionFetcher(
       new MojoProvisionFetcher(std::move(provision_fetcher_ptr)));
 }
 
-class AndroidMojoMediaClient : public MojoMediaClient {
- public:
-  AndroidMojoMediaClient() {}
+}  // namespace
 
-  // MojoMediaClient overrides.
-  scoped_ptr<CdmFactory> CreateCdmFactory(
-      mojo::shell::mojom::InterfaceProvider* service_provider) override {
-    return make_scoped_ptr(new AndroidCdmFactory(
-        base::Bind(&CreateProvisionFetcher, service_provider)));
-  }
+AndroidMojoMediaClient::AndroidMojoMediaClient() {}
 
- private:
-  DISALLOW_COPY_AND_ASSIGN(AndroidMojoMediaClient);
-};
-}  // namespace (anonymous)
+AndroidMojoMediaClient::~AndroidMojoMediaClient() {}
 
-scoped_ptr<MojoMediaClient> MojoMediaClient::Create() {
-  return make_scoped_ptr(new AndroidMojoMediaClient());
+// MojoMediaClient overrides.
+scoped_ptr<CdmFactory> AndroidMojoMediaClient::CreateCdmFactory(
+    mojo::shell::mojom::InterfaceProvider* service_provider) {
+  return make_scoped_ptr(new AndroidCdmFactory(
+      base::Bind(&CreateProvisionFetcher, service_provider)));
 }
 
 }  // namespace media
diff --git a/media/mojo/services/android_mojo_media_client.h b/media/mojo/services/android_mojo_media_client.h
new file mode 100644
index 0000000..11a14db
--- /dev/null
+++ b/media/mojo/services/android_mojo_media_client.h
@@ -0,0 +1,28 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_MOJO_SERVICES_ANDROID_MOJO_MEDIA_CLIENT_H_
+#define MEDIA_MOJO_SERVICES_ANDROID_MOJO_MEDIA_CLIENT_H_
+
+#include "base/macros.h"
+#include "media/mojo/services/mojo_media_client.h"
+
+namespace media {
+
+class AndroidMojoMediaClient : public MojoMediaClient {
+ public:
+  AndroidMojoMediaClient();
+  ~AndroidMojoMediaClient() final;
+
+  // MojoMediaClient implementation.
+  scoped_ptr<CdmFactory> CreateCdmFactory(
+      mojo::shell::mojom::InterfaceProvider* service_provider) final;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AndroidMojoMediaClient);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_MOJO_SERVICES_ANDROID_MOJO_MEDIA_CLIENT_H_
diff --git a/media/mojo/services/default_mojo_media_client.cc b/media/mojo/services/default_mojo_media_client.cc
index 4facbd1..c602f64 100644
--- a/media/mojo/services/default_mojo_media_client.cc
+++ b/media/mojo/services/default_mojo_media_client.cc
@@ -2,13 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "media/mojo/services/mojo_media_client.h"
+#include "media/mojo/services/default_mojo_media_client.h"
 
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 #include "media/audio/audio_manager_base.h"
 #include "media/audio/audio_output_stream_sink.h"
-#include "media/audio/fake_audio_log_factory.h"
 #include "media/base/audio_hardware_config.h"
 #include "media/base/media.h"
 #include "media/base/null_video_sink.h"
@@ -18,72 +15,55 @@
 
 namespace media {
 
-namespace {
-class DefaultMojoMediaClient : public MojoMediaClient {
- public:
-  DefaultMojoMediaClient() {}
-
-  // MojoMediaClient overrides.
-  void Initialize() override {
-    InitializeMediaLibrary();
-    // TODO(dalecurtis): We should find a single owner per process for the audio
-    // manager or make it a lazy instance.  It's not safe to call Get()/Create()
-    // across multiple threads...
-    //
-    // TODO(dalecurtis): Eventually we'll want something other than a fake audio
-    // log factory here too.  We should probably at least DVLOG() such info.
-    AudioManager* audio_manager = AudioManager::Get();
-    if (!audio_manager)
-      audio_manager = media::AudioManager::Create(&fake_audio_log_factory_);
-
-    audio_hardware_config_.reset(new AudioHardwareConfig(
-        audio_manager->GetInputStreamParameters(
-            AudioManagerBase::kDefaultDeviceId),
-        audio_manager->GetDefaultOutputStreamParameters()));
-  }
-
-  scoped_ptr<RendererFactory> CreateRendererFactory(
-      const scoped_refptr<MediaLog>& media_log) override {
-    return make_scoped_ptr(new DefaultRendererFactory(media_log, nullptr,
-                                                      *audio_hardware_config_));
-  }
-
-  AudioRendererSink* CreateAudioRendererSink() override {
-    if (!audio_renderer_sink_)
-      audio_renderer_sink_ = new AudioOutputStreamSink();
+DefaultMojoMediaClient::DefaultMojoMediaClient() {}
+
+DefaultMojoMediaClient::~DefaultMojoMediaClient() {}
+
+void DefaultMojoMediaClient::Initialize() {
+  InitializeMediaLibrary();
+  // TODO(dalecurtis): We should find a single owner per process for the audio
+  // manager or make it a lazy instance.  It's not safe to call Get()/Create()
+  // across multiple threads...
+  //
+  // TODO(dalecurtis): Eventually we'll want something other than a fake audio
+  // log factory here too.  We should probably at least DVLOG() such info.
+  AudioManager* audio_manager = AudioManager::Get();
+  if (!audio_manager)
+    audio_manager = media::AudioManager::Create(&fake_audio_log_factory_);
+
+  audio_hardware_config_.reset(new AudioHardwareConfig(
+      audio_manager->GetInputStreamParameters(
+          AudioManagerBase::kDefaultDeviceId),
+      audio_manager->GetDefaultOutputStreamParameters()));
+}
 
-    return audio_renderer_sink_.get();
-  }
+scoped_ptr<RendererFactory> DefaultMojoMediaClient::CreateRendererFactory(
+    const scoped_refptr<MediaLog>& media_log) {
+  return make_scoped_ptr(
+      new DefaultRendererFactory(media_log, nullptr, *audio_hardware_config_));
+}
 
-  VideoRendererSink* CreateVideoRendererSink(
-      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) override {
-    if (!video_renderer_sink_) {
-      video_renderer_sink_ = make_scoped_ptr(
-          new NullVideoSink(false, base::TimeDelta::FromSecondsD(1.0 / 60),
-                            NullVideoSink::NewFrameCB(), task_runner));
-    }
+AudioRendererSink* DefaultMojoMediaClient::CreateAudioRendererSink() {
+  if (!audio_renderer_sink_)
+    audio_renderer_sink_ = new AudioOutputStreamSink();
 
-    return video_renderer_sink_.get();
-  }
+  return audio_renderer_sink_.get();
+}
 
-  scoped_ptr<CdmFactory> CreateCdmFactory(
-      mojo::shell::mojom::InterfaceProvider* /* service_provider */) override {
-    return make_scoped_ptr(new DefaultCdmFactory());
+VideoRendererSink* DefaultMojoMediaClient::CreateVideoRendererSink(
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) {
+  if (!video_renderer_sink_) {
+    video_renderer_sink_ = make_scoped_ptr(
+        new NullVideoSink(false, base::TimeDelta::FromSecondsD(1.0 / 60),
+                          NullVideoSink::NewFrameCB(), task_runner));
   }
 
- private:
-  FakeAudioLogFactory fake_audio_log_factory_;
-  scoped_ptr<AudioHardwareConfig> audio_hardware_config_;
-  scoped_refptr<AudioRendererSink> audio_renderer_sink_;
-  scoped_ptr<VideoRendererSink> video_renderer_sink_;
-
-  DISALLOW_COPY_AND_ASSIGN(DefaultMojoMediaClient);
-};
-
-}  // namespace (anonymous)
+  return video_renderer_sink_.get();
+}
 
-scoped_ptr<MojoMediaClient> MojoMediaClient::Create() {
-  return make_scoped_ptr(new DefaultMojoMediaClient());
+scoped_ptr<CdmFactory> DefaultMojoMediaClient::CreateCdmFactory(
+    mojo::shell::mojom::InterfaceProvider* /* service_provider */) {
+  return make_scoped_ptr(new DefaultCdmFactory());
 }
 
 }  // namespace media
diff --git a/media/mojo/services/default_mojo_media_client.h b/media/mojo/services/default_mojo_media_client.h
new file mode 100644
index 0000000..7498e25
--- /dev/null
+++ b/media/mojo/services/default_mojo_media_client.h
@@ -0,0 +1,47 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_MOJO_SERVICES_DEFAULT_MOJO_MEDIA_CLIENT_H_
+#define MEDIA_MOJO_SERVICES_DEFAULT_MOJO_MEDIA_CLIENT_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/audio/fake_audio_log_factory.h"
+#include "media/mojo/services/mojo_media_client.h"
+
+namespace media {
+
+class AudioHardwareConfig;
+class AudioRendererSink;
+class VideoRendererSink;
+
+// Default MojoMediaClient for MojoMediaApplication.
+class DefaultMojoMediaClient : public MojoMediaClient {
+ public:
+  DefaultMojoMediaClient();
+  ~DefaultMojoMediaClient() final;
+
+  // MojoMediaClient implementation.
+  void Initialize() final;
+  scoped_ptr<RendererFactory> CreateRendererFactory(
+      const scoped_refptr<MediaLog>& media_log) final;
+  AudioRendererSink* CreateAudioRendererSink() final;
+  VideoRendererSink* CreateVideoRendererSink(
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) final;
+  scoped_ptr<CdmFactory> CreateCdmFactory(
+      mojo::shell::mojom::InterfaceProvider* /* service_provider */) final;
+
+ private:
+  FakeAudioLogFactory fake_audio_log_factory_;
+  scoped_ptr<AudioHardwareConfig> audio_hardware_config_;
+  scoped_refptr<AudioRendererSink> audio_renderer_sink_;
+  scoped_ptr<VideoRendererSink> video_renderer_sink_;
+
+  DISALLOW_COPY_AND_ASSIGN(DefaultMojoMediaClient);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_MOJO_SERVICES_DEFAULT_MOJO_MEDIA_CLIENT_H_
diff --git a/media/mojo/services/main.cc b/media/mojo/services/main.cc
index b3df5c8..2ab7d06 100644
--- a/media/mojo/services/main.cc
+++ b/media/mojo/services/main.cc
@@ -14,8 +14,8 @@ MojoResult MojoMain(MojoHandle mojo_handle) {
   mojo::ApplicationRunner::InitBaseCommandLine();
   mojo::InitLogging();
 
-  scoped_ptr<mojo::ShellClient> app_delegate =
+  scoped_ptr<mojo::ShellClient> shell_client =
       media::MojoMediaApplication::CreateApp();
-  mojo::ApplicationRunner runner(app_delegate.release());
+  mojo::ApplicationRunner runner(shell_client.release());
   return runner.Run(mojo_handle, false /* init_base */);
 }
diff --git a/media/mojo/services/mojo_cdm_service_context.h b/media/mojo/services/mojo_cdm_service_context.h
index 4b797f9..b3592be 100644
--- a/media/mojo/services/mojo_cdm_service_context.h
+++ b/media/mojo/services/mojo_cdm_service_context.h
@@ -12,7 +12,6 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "media/base/cdm_context.h"
-#include "media/base/media_export.h"
 
 namespace media {
 
diff --git a/media/mojo/services/mojo_media_application.cc b/media/mojo/services/mojo_media_application.cc
index 05a72f3..8a92b02 100644
--- a/media/mojo/services/mojo_media_application.cc
+++ b/media/mojo/services/mojo_media_application.cc
@@ -12,12 +12,36 @@
 #include "mojo/shell/public/cpp/connection.h"
 #include "mojo/shell/public/cpp/shell.h"
 
+#if defined(OS_ANDROID)
+#include "media/mojo/services/android_mojo_media_client.h"
+#else
+#include "media/mojo/services/default_mojo_media_client.h"
+#endif
+
 namespace media {
 
+#if defined(OS_ANDROID)
+using DefaultClient = AndroidMojoMediaClient;
+#else
+using DefaultClient = DefaultMojoMediaClient;
+#endif
+
 // static
 scoped_ptr<mojo::ShellClient> MojoMediaApplication::CreateApp() {
   return scoped_ptr<mojo::ShellClient>(
-      new MojoMediaApplication(MojoMediaClient::Create()));
+      new MojoMediaApplication(make_scoped_ptr(new DefaultClient())));
+}
+
+// static
+scoped_ptr<mojo::ShellClient> MojoMediaApplication::CreateAppWithClient(
+    const CreateMojoMediaClientCB& create_mojo_media_client_cb) {
+  scoped_ptr<MojoMediaClient> mojo_media_client =
+      create_mojo_media_client_cb.Run();
+  if (!mojo_media_client)
+    return nullptr;
+
+  return scoped_ptr<mojo::ShellClient>(
+      new MojoMediaApplication(std::move(mojo_media_client)));
 }
 
 // TODO(xhwang): Hook up MediaLog when possible.
@@ -25,13 +49,15 @@ MojoMediaApplication::MojoMediaApplication(
     scoped_ptr<MojoMediaClient> mojo_media_client)
     : mojo_media_client_(std::move(mojo_media_client)),
       shell_(nullptr),
-      media_log_(new MediaLog()) {}
+      media_log_(new MediaLog()) {
+  DCHECK(mojo_media_client_);
+}
 
 MojoMediaApplication::~MojoMediaApplication() {}
 
 void MojoMediaApplication::Initialize(mojo::Shell* shell,
-                                      const std::string& url,
-                                      uint32_t id) {
+                                      const std::string& /* url */,
+                                      uint32_t /* id */) {
   shell_ = shell;
   mojo_media_client_->Initialize();
 }
diff --git a/media/mojo/services/mojo_media_application.h b/media/mojo/services/mojo_media_application.h
index 71b1e06..c1e24df 100644
--- a/media/mojo/services/mojo_media_application.h
+++ b/media/mojo/services/mojo_media_application.h
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "media/mojo/interfaces/service_factory.mojom.h"
 #include "mojo/shell/public/cpp/interface_factory_impl.h"
@@ -17,12 +18,22 @@ class MojoMediaApplication
     : public mojo::ShellClient,
       public mojo::InterfaceFactory<interfaces::ServiceFactory> {
  public:
+  // Callback to create a MojoMediaClient.
+  using CreateMojoMediaClientCB = base::Callback<scoped_ptr<MojoMediaClient>()>;
+
+  // Creates MojoMediaApplication using the default MojoMediaClient.
   static scoped_ptr<mojo::ShellClient> CreateApp();
 
-  explicit MojoMediaApplication(scoped_ptr<MojoMediaClient> mojo_media_client);
+  // Creates MojoMediaApplication using the MojoMediaClient provided by
+  // |create_mojo_media_client_cb|.
+  static scoped_ptr<mojo::ShellClient> CreateAppWithClient(
+      const CreateMojoMediaClientCB& create_mojo_media_client_cb);
+
   ~MojoMediaApplication() final;
 
  private:
+  explicit MojoMediaApplication(scoped_ptr<MojoMediaClient> mojo_media_client);
+
   // mojo::ShellClient implementation.
   void Initialize(mojo::Shell* shell,
                   const std::string& url,
@@ -33,7 +44,11 @@ class MojoMediaApplication
   void Create(mojo::Connection* connection,
               mojo::InterfaceRequest<interfaces::ServiceFactory> request) final;
 
+  // Note: Since each instance runs on a different thread, do not share a common
+  // MojoMediaClient with other instances to avoid threading issues. Hence using
+  // a scoped_ptr here.
   scoped_ptr<MojoMediaClient> mojo_media_client_;
+
   mojo::Shell* shell_;
   scoped_refptr<MediaLog> media_log_;
 };
diff --git a/media/mojo/services/mojo_media_client.h b/media/mojo/services/mojo_media_client.h
index 4e4d39b..2798aaa 100644
--- a/media/mojo/services/mojo_media_client.h
+++ b/media/mojo/services/mojo_media_client.h
@@ -5,13 +5,16 @@
 #ifndef MEDIA_MOJO_SERVICES_MOJO_MEDIA_CLIENT_H_
 #define MEDIA_MOJO_SERVICES_MOJO_MEDIA_CLIENT_H_
 
-#include "base/single_thread_task_runner.h"
 #include "media/base/audio_renderer_sink.h"
 #include "media/base/cdm_factory.h"
 #include "media/base/media_log.h"
 #include "media/base/renderer_factory.h"
 #include "media/base/video_renderer_sink.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace mojo {
 namespace shell {
 namespace mojom {
@@ -26,8 +29,6 @@ class MojoMediaClient {
  public:
   virtual ~MojoMediaClient();
 
-  static scoped_ptr<MojoMediaClient> Create();
-
   // Called exactly once before any other method.
   virtual void Initialize();
   // Returns the RendererFactory to be used by MojoRendererService. If returns
diff --git a/media/mojo/services/mojo_renderer_factory.h b/media/mojo/services/mojo_renderer_factory.h
index 06d6447..5e0610c 100644
--- a/media/mojo/services/mojo_renderer_factory.h
+++ b/media/mojo/services/mojo_renderer_factory.h
@@ -6,7 +6,6 @@
 #define MEDIA_MOJO_SERVICES_MOJO_RENDERER_FACTORY_H_
 
 #include "base/macros.h"
-#include "media/base/media_export.h"
 #include "media/base/renderer_factory.h"
 #include "media/mojo/interfaces/renderer.mojom.h"
 #include "mojo/public/cpp/bindings/interface_ptr.h"