Reland: Web MIDI: split build rules for media/midi

Changes from the first coommit.
- Define right dependencies to xdisplaycheck
- Fix build rules for midi_unittests_apk to run on Android
- Rebase error fixes (build rule deopendency adjustments)

Original commit is:
https://crrev.com/31624cad1a3b5cf26950b864837ba44b3aa38331

Original description follows:

Split MIDI related stuffs from media as a component in build files.
Also, MIDI related unit tests are split into midi_unittests.

BUG=475869
TEST=git cl try
TEST=ninja midi_unittests_apk && ./build/android/test_runner.py gtest midi_unittests

Review URL: https://codereview.chromium.org/1065743003

Cr-Commit-Position: refs/heads/master@{#327712}

18 files changed, 567 insertions, 181 deletions

diff --git a/media/BUILD.gn b/media/BUILD.gn
index 4c8d52a..b62b0ea 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -32,9 +32,6 @@ config("media_config") {
   if (use_cras) {
     defines += [ "USE_CRAS" ]
   }
-  if (use_alsa) {
-    defines += [ "USE_ALSA" ]
-  }
 }
 
 config("media_implementation") {
@@ -178,30 +175,6 @@ component("media") {
     "formats/webm/webm_video_client.h",
     "formats/webm/webm_webvtt_parser.cc",
     "formats/webm/webm_webvtt_parser.h",
-    "midi/midi_manager.cc",
-    "midi/midi_manager.h",
-    "midi/midi_manager_mac.cc",
-    "midi/midi_manager_mac.h",
-    "midi/midi_manager_usb.cc",
-    "midi/midi_manager_usb.h",
-    "midi/midi_manager_win.cc",
-    "midi/midi_manager_win.h",
-    "midi/midi_message_queue.cc",
-    "midi/midi_message_queue.h",
-    "midi/midi_message_util.cc",
-    "midi/midi_message_util.h",
-    "midi/midi_port_info.cc",
-    "midi/midi_port_info.h",
-    "midi/midi_scheduler.cc",
-    "midi/midi_scheduler.h",
-    "midi/usb_midi_descriptor_parser.cc",
-    "midi/usb_midi_descriptor_parser.h",
-    "midi/usb_midi_device.h",
-    "midi/usb_midi_input_stream.cc",
-    "midi/usb_midi_input_stream.h",
-    "midi/usb_midi_jack.h",
-    "midi/usb_midi_output_stream.cc",
-    "midi/usb_midi_output_stream.h",
     "renderers/audio_renderer_impl.cc",
     "renderers/audio_renderer_impl.h",
     "renderers/gpu_video_accelerator_factories.h",
@@ -337,11 +310,6 @@ component("media") {
 
   if (is_android) {
     sources += [
-      "midi/midi_manager_android.cc",
-      "midi/usb_midi_device_android.cc",
-      "midi/usb_midi_device_android.h",
-      "midi/usb_midi_device_factory_android.cc",
-      "midi/usb_midi_device_factory_android.h",
       "video/capture/android/video_capture_device_android.cc",
       "video/capture/android/video_capture_device_android.h",
       "video/capture/android/video_capture_device_factory_android.cc",
@@ -370,15 +338,6 @@ component("media") {
     ]
   }
 
-  if (use_alsa && use_udev) {
-    libs += [ "asound" ]
-    sources += [
-      "midi/midi_manager_alsa.cc",
-      "midi/midi_manager_alsa.h",
-    ]
-    deps += [ "//device/udev_linux" ]
-  }
-
   # A simple WebM encoder for animated avatars on ChromeOS.
 
   if (use_ozone) {
@@ -402,7 +361,6 @@ component("media") {
       "//third_party/decklink",
     ]
     libs += [
-      "CoreMIDI.framework",
       "CoreVideo.framework",
       "OpenGL.framework",
       "QTKit.framework",
@@ -421,8 +379,6 @@ component("media") {
   }
 
   if (is_win) {
-    deps += [ "//device/usb" ]
-
     libs += [
       "mf.lib",
       "mfplat.lib",
@@ -575,13 +531,6 @@ test("media_unittests") {
     "formats/webm/webm_parser_unittest.cc",
     "formats/webm/webm_tracks_parser_unittest.cc",
     "formats/webm/webm_webvtt_parser_unittest.cc",
-    "midi/midi_manager_unittest.cc",
-    "midi/midi_manager_usb_unittest.cc",
-    "midi/midi_message_queue_unittest.cc",
-    "midi/midi_message_util_unittest.cc",
-    "midi/usb_midi_descriptor_parser_unittest.cc",
-    "midi/usb_midi_input_stream_unittest.cc",
-    "midi/usb_midi_output_stream_unittest.cc",
     "renderers/audio_renderer_impl_unittest.cc",
     "renderers/renderer_impl_unittest.cc",
     "renderers/video_renderer_impl_unittest.cc",
@@ -669,18 +618,8 @@ test("media_unittests") {
   }
 
   if (is_mac) {
-    sources += [
-      "midi/midi_manager_mac_unittest.cc",
-      "video/capture/mac/video_capture_device_factory_mac_unittest.mm",
-    ]
-    libs = [
-      # Required by midi_manager_mac_unittest.cc.
-      "CoreMIDI.framework",
-    ]
-  }
-
-  if (use_alsa && use_udev) {
-    sources += [ "midi/midi_manager_alsa_unittest.cc" ]
+    sources +=
+        [ "video/capture/mac/video_capture_device_factory_mac_unittest.mm" ]
   }
 
   #      include_dirs += [
diff --git a/media/OWNERS b/media/OWNERS
index b7c2a18..fdb8c86 100644
--- a/media/OWNERS
+++ b/media/OWNERS
@@ -6,10 +6,5 @@ scherkus@chromium.org
 wolenetz@chromium.org
 xhwang@chromium.org
 
-# Build rules for Web MIDI
-per-file BUILD.gn=toyoshim@chromium.org
-per-file *.gyp=toyoshim@chromium.org
-per-file *.gypi=toyoshim@chromium.org
-
 per-file *.isolate=csharp@chromium.org
 per-file *.isolate=maruel@chromium.org
diff --git a/media/base/android/BUILD.gn b/media/base/android/BUILD.gn
index c407b17..9ab5265 100644
--- a/media/base/android/BUILD.gn
+++ b/media/base/android/BUILD.gn
@@ -87,8 +87,6 @@ generate_jni("media_jni_headers") {
     "java/src/org/chromium/media/MediaDrmBridge.java",
     "java/src/org/chromium/media/MediaPlayerBridge.java",
     "java/src/org/chromium/media/MediaPlayerListener.java",
-    "java/src/org/chromium/media/UsbMidiDeviceAndroid.java",
-    "java/src/org/chromium/media/UsbMidiDeviceFactoryAndroid.java",
     "java/src/org/chromium/media/WebAudioMediaCodecBridge.java",
   ]
   jni_package = "media"
diff --git a/media/base/android/media_jni_registrar.cc b/media/base/android/media_jni_registrar.cc
index c9b8489..9ab40e4 100644
--- a/media/base/android/media_jni_registrar.cc
+++ b/media/base/android/media_jni_registrar.cc
@@ -15,8 +15,6 @@
 #include "media/base/android/media_player_bridge.h"
 #include "media/base/android/media_player_listener.h"
 #include "media/base/android/webaudio_media_codec_bridge.h"
-#include "media/midi/usb_midi_device_android.h"
-#include "media/midi/usb_midi_device_factory_android.h"
 #include "media/video/capture/android/video_capture_device_android.h"
 #include "media/video/capture/android/video_capture_device_factory_android.h"
 
@@ -35,10 +33,6 @@ static base::android::RegistrationMethod kMediaRegisteredMethods[] = {
     MediaPlayerBridge::RegisterMediaPlayerBridge },
   { "MediaPlayerListener",
     MediaPlayerListener::RegisterMediaPlayerListener },
-  { "UsbMidiDevice",
-    UsbMidiDeviceAndroid::RegisterUsbMidiDevice },
-  { "UsbMidiDeviceFactory",
-    UsbMidiDeviceFactoryAndroid::RegisterUsbMidiDeviceFactory },
   { "VideoCaptureDevice",
     VideoCaptureDeviceAndroid::RegisterVideoCaptureDevice },
   { "VideoCaptureDeviceFactory",
diff --git a/media/media.gyp b/media/media.gyp
index c228c83..dac02a3 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -512,37 +512,6 @@
         'formats/webm/webm_video_client.cc',
         'formats/webm/webm_video_client.h',
         'formats/webm/webm_webvtt_parser.cc',
-        'midi/midi_manager.cc',
-        'midi/midi_manager.h',
-        'midi/midi_manager_alsa.cc',
-        'midi/midi_manager_alsa.h',
-        'midi/midi_manager_android.cc',
-        'midi/midi_manager_mac.cc',
-        'midi/midi_manager_mac.h',
-        'midi/midi_manager_usb.cc',
-        'midi/midi_manager_usb.h',
-        'midi/midi_manager_win.cc',
-        'midi/midi_manager_win.h',
-        'midi/midi_message_queue.cc',
-        'midi/midi_message_queue.h',
-        'midi/midi_message_util.cc',
-        'midi/midi_message_util.h',
-        'midi/midi_port_info.cc',
-        'midi/midi_port_info.h',
-        'midi/midi_scheduler.cc',
-        'midi/midi_scheduler.h',
-        'midi/usb_midi_descriptor_parser.cc',
-        'midi/usb_midi_descriptor_parser.h',
-        'midi/usb_midi_device.h',
-        'midi/usb_midi_device_android.cc',
-        'midi/usb_midi_device_android.h',
-        'midi/usb_midi_device_factory_android.cc',
-        'midi/usb_midi_device_factory_android.h',
-        'midi/usb_midi_input_stream.cc',
-        'midi/usb_midi_input_stream.h',
-        'midi/usb_midi_jack.h',
-        'midi/usb_midi_output_stream.cc',
-        'midi/usb_midi_output_stream.h',
         'ozone/media_ozone_platform.cc',
         'ozone/media_ozone_platform.h',
         'renderers/audio_renderer_impl.cc',
@@ -956,7 +925,6 @@
               '$(SDKROOT)/System/Library/Frameworks/AudioToolbox.framework',
               '$(SDKROOT)/System/Library/Frameworks/AudioUnit.framework',
               '$(SDKROOT)/System/Library/Frameworks/CoreAudio.framework',
-              '$(SDKROOT)/System/Library/Frameworks/CoreMIDI.framework',
               '$(SDKROOT)/System/Library/Frameworks/CoreVideo.framework',
               '$(SDKROOT)/System/Library/Frameworks/OpenGL.framework',
               '$(SDKROOT)/System/Library/Frameworks/QTKit.framework',
@@ -964,9 +932,6 @@
           },
         }],
         ['OS=="win"', {
-          'dependencies': [
-            '../device/usb/usb.gyp:device_usb',
-          ],
           'link_settings':  {
             'libraries': [
               '-lmf.lib',
@@ -1093,16 +1058,6 @@
             'filters/source_buffer_platform.h',
           ]
         }],
-        ['use_udev==1', {
-          'dependencies': [
-            '../device/udev_linux/udev.gyp:udev_linux',
-          ],
-        }, {  # use_udev==0
-          'sources!': [
-            'midi/midi_manager_alsa.cc',
-            'midi/midi_manager_alsa.h',
-          ],
-        }],
       ],  # conditions
       'target_conditions': [
         ['OS == "ios" and _toolset != "host"', {
@@ -1274,13 +1229,6 @@
         'formats/webm/webm_parser_unittest.cc',
         'formats/webm/webm_tracks_parser_unittest.cc',
         'formats/webm/webm_webvtt_parser_unittest.cc',
-        'midi/midi_manager_unittest.cc',
-        'midi/midi_manager_usb_unittest.cc',
-        'midi/midi_message_queue_unittest.cc',
-        'midi/midi_message_util_unittest.cc',
-        'midi/usb_midi_descriptor_parser_unittest.cc',
-        'midi/usb_midi_input_stream_unittest.cc',
-        'midi/usb_midi_output_stream_unittest.cc',
         'renderers/audio_renderer_impl_unittest.cc',
         'renderers/renderer_impl_unittest.cc',
         'renderers/video_renderer_impl_unittest.cc',
@@ -1413,15 +1361,9 @@
         }],
         ['OS=="mac"', {
           'sources': [
-            'midi/midi_manager_mac_unittest.cc',
             'video/capture/mac/video_capture_device_factory_mac_unittest.mm',
           ]
         }],
-        ['use_alsa==1 and use_udev==1', {
-          'sources': [
-            'midi/midi_manager_alsa_unittest.cc',
-          ]
-        }],
         ['use_x11==1', {
           'dependencies': [
             '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
@@ -1705,8 +1647,6 @@
             'base/android/java/src/org/chromium/media/MediaDrmBridge.java',
             'base/android/java/src/org/chromium/media/MediaPlayerBridge.java',
             'base/android/java/src/org/chromium/media/MediaPlayerListener.java',
-            'base/android/java/src/org/chromium/media/UsbMidiDeviceAndroid.java',
-            'base/android/java/src/org/chromium/media/UsbMidiDeviceFactoryAndroid.java',
             'base/android/java/src/org/chromium/media/WebAudioMediaCodecBridge.java',
           ],
           'variables': {
diff --git a/media/midi/BUILD.gn b/media/midi/BUILD.gn
new file mode 100644
index 0000000..0faa867
--- /dev/null
+++ b/media/midi/BUILD.gn
@@ -0,0 +1,172 @@
+# Copyright 2015 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.
+
+import("//build/config/android/config.gni")
+import("//build/config/features.gni")
+import("//build/config/ui.gni")
+import("//media/media_options.gni")
+import("//testing/test.gni")
+
+if (is_android) {
+  # For generate_jni().
+  import("//build/config/android/rules.gni")
+}
+
+# Common configuration for targets in the media/midi directory.
+config("midi_config") {
+  if (use_alsa) {
+    defines = [
+      "USE_ALSA",
+      "USE_UDEV",
+    ]
+  }
+
+  visibility = [ ":*" ]
+}
+
+# USB MIDI specific source files that are used in Android port, and unit tests.
+source_set("usb_midi") {
+  sources = [
+    "midi_manager_usb.cc",
+    "midi_manager_usb.h",
+    "usb_midi_descriptor_parser.cc",
+    "usb_midi_descriptor_parser.h",
+    "usb_midi_device.h",
+    "usb_midi_input_stream.cc",
+    "usb_midi_input_stream.h",
+    "usb_midi_jack.h",
+    "usb_midi_output_stream.cc",
+    "usb_midi_output_stream.h",
+  ]
+
+  defines = [ "MEDIA_IMPLEMENTATION" ]
+  deps = [
+    "//base",
+  ]
+}
+
+# Android specific Java source files that are used to generate jni header files.
+if (is_android) {
+  android_library("midi_java") {
+    deps = [
+      "//base:base_java",
+    ]
+
+    DEPRECATED_java_in_dir = "java/src"
+  }
+
+  generate_jni("midi_jni_headers") {
+    sources = [
+      "java/src/org/chromium/media/midi/UsbMidiDeviceAndroid.java",
+      "java/src/org/chromium/media/midi/UsbMidiDeviceFactoryAndroid.java",
+    ]
+    jni_package = "media/midi"
+  }
+}
+
+component("midi") {
+  sources = [
+    "midi_manager.cc",
+    "midi_manager.h",
+    "midi_manager_mac.cc",
+    "midi_manager_mac.h",
+    "midi_manager_win.cc",
+    "midi_manager_win.h",
+    "midi_message_queue.cc",
+    "midi_message_queue.h",
+    "midi_message_util.cc",
+    "midi_message_util.h",
+    "midi_port_info.cc",
+    "midi_port_info.h",
+    "midi_scheduler.cc",
+    "midi_scheduler.h",
+  ]
+
+  configs += [ ":midi_config" ]
+
+  defines = [ "MEDIA_IMPLEMENTATION" ]
+  deps = []
+  libs = []
+
+  if (is_android) {
+    sources += [
+      "midi_jni_registrar.cc",
+      "midi_jni_registrar.h",
+      "midi_manager_android.cc",
+      "usb_midi_device_android.cc",
+      "usb_midi_device_android.h",
+      "usb_midi_device_factory_android.cc",
+      "usb_midi_device_factory_android.h",
+    ]
+
+    deps += [
+      "//base:i18n",
+      ":midi_jni_headers",
+      ":usb_midi",
+    ]
+  }
+
+  if (is_mac) {
+    libs += [
+      "CoreAudio.framework",
+      "CoreMIDI.framework",
+    ]
+  }
+
+  if (is_win) {
+    deps += [ "//device/usb" ]
+  }
+
+  if (use_alsa && use_udev) {
+    deps += [
+      "//crypto",
+      "//crypto:platform",
+    ]
+    libs += [ "asound" ]
+    sources += [
+      "midi_manager_alsa.cc",
+      "midi_manager_alsa.h",
+    ]
+  }
+
+  if (use_udev) {
+    deps += [ "//device/udev_linux" ]
+  }
+}
+
+test("midi_unittests") {
+  sources = [
+    "midi_manager_unittest.cc",
+    "midi_manager_usb_unittest.cc",
+    "midi_message_queue_unittest.cc",
+    "midi_message_util_unittest.cc",
+    "usb_midi_descriptor_parser_unittest.cc",
+    "usb_midi_input_stream_unittest.cc",
+    "usb_midi_output_stream_unittest.cc",
+  ]
+
+  configs += [ ":midi_config" ]
+  deps = [
+    ":midi",
+    "//base/test/:run_all_unittests",
+    "//base/test/:test_support",
+    "//testing/gtest",
+  ]
+
+  if (!is_android) {
+    deps += [ ":usb_midi" ]
+  }
+
+  if (is_mac) {
+    sources += [ "midi_manager_mac_unittest.cc" ]
+  }
+
+  if (use_alsa && use_udev) {
+    sources += [ "midi_manager_alsa_unittest.cc" ]
+  }
+
+  if (use_x11) {
+    deps += [ "//tools/xdisplaycheck" ]
+  }
+}
diff --git a/media/base/android/java/src/org/chromium/media/UsbMidiDeviceAndroid.java b/media/midi/java/src/org/chromium/media/midi/UsbMidiDeviceAndroid.java
index c581131..4bdd5f5 100644
--- a/media/base/android/java/src/org/chromium/media/UsbMidiDeviceAndroid.java
+++ b/media/midi/java/src/org/chromium/media/midi/UsbMidiDeviceAndroid.java
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-package org.chromium.media;
+package org.chromium.media.midi;
 
 import android.annotation.TargetApi;
 import android.hardware.usb.UsbConstants;
@@ -28,7 +28,7 @@ import java.util.Map;
  * Owned by its native counterpart declared in usb_midi_device_android.h.
  * Refer to that class for general comments.
  */
-@JNINamespace("media")
+@JNINamespace("media::midi")
 class UsbMidiDeviceAndroid {
     /**
      * A connection handle for this device.
@@ -184,14 +184,14 @@ class UsbMidiDeviceAndroid {
      */
     private void postOnDataEvent(final int endpointNumber, final byte[] bs) {
         mHandler.post(new Runnable() {
-                @Override
-                public void run() {
-                    if (mIsClosed) {
-                        return;
-                    }
-                    nativeOnData(mNativePointer, endpointNumber, bs);
+            @Override
+            public void run() {
+                if (mIsClosed) {
+                    return;
                 }
-            });
+                nativeOnData(mNativePointer, endpointNumber, bs);
+            }
+        });
     }
 
     UsbDevice getUsbDevice() {
@@ -321,7 +321,6 @@ class UsbMidiDeviceAndroid {
         return position;
     }
 
-    private static native void nativeOnData(long nativeUsbMidiDeviceAndroid,
-                                            int endpointNumber,
-                                            byte[] data);
+    private static native void nativeOnData(
+            long nativeUsbMidiDeviceAndroid, int endpointNumber, byte[] data);
 }
diff --git a/media/base/android/java/src/org/chromium/media/UsbMidiDeviceFactoryAndroid.java b/media/midi/java/src/org/chromium/media/midi/UsbMidiDeviceFactoryAndroid.java
index 814bb17..e003332 100644
--- a/media/base/android/java/src/org/chromium/media/UsbMidiDeviceFactoryAndroid.java
+++ b/media/midi/java/src/org/chromium/media/midi/UsbMidiDeviceFactoryAndroid.java
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-package org.chromium.media;
+package org.chromium.media.midi;
 
 import android.app.PendingIntent;
 import android.content.BroadcastReceiver;
@@ -28,7 +28,7 @@ import java.util.Set;
  * Owned by its native counterpart declared in
  * usb_midi_device_factory_android.h. Refer to that class for general comments.
  */
-@JNINamespace("media")
+@JNINamespace("media::midi")
 class UsbMidiDeviceFactoryAndroid {
     /**
      * The UsbManager of this system.
@@ -60,8 +60,7 @@ class UsbMidiDeviceFactoryAndroid {
      */
     private long mNativePointer;
 
-    private static final String ACTION_USB_PERMISSION =
-            "org.chromium.media.USB_PERMISSION";
+    private static final String ACTION_USB_PERMISSION = "org.chromium.media.USB_PERMISSION";
 
     /**
      * Constructs a UsbMidiDeviceAndroid.
@@ -125,7 +124,7 @@ class UsbMidiDeviceFactoryAndroid {
             mIsEnumeratingDevices = false;
             return false;
         }
-        for (UsbDevice device: devices.values()) {
+        for (UsbDevice device : devices.values()) {
             requestDevicePermissionIfNecessary(context, device);
         }
         return true;
@@ -138,7 +137,7 @@ class UsbMidiDeviceFactoryAndroid {
      * @param device a USB device
      */
     private void requestDevicePermissionIfNecessary(Context context, UsbDevice device) {
-        for (UsbDevice d: mRequestedDevices) {
+        for (UsbDevice d : mRequestedDevices) {
             if (d.getDeviceId() == device.getDeviceId()) {
                 // It is already requested.
                 return;
@@ -150,8 +149,9 @@ class UsbMidiDeviceFactoryAndroid {
             if (iface.getInterfaceClass() == UsbConstants.USB_CLASS_AUDIO
                     && iface.getInterfaceSubclass() == UsbMidiDeviceAndroid.MIDI_SUBCLASS) {
                 // There is at least one interface supporting MIDI.
-                mUsbManager.requestPermission(device, PendingIntent.getBroadcast(
-                        context, 0, new Intent(ACTION_USB_PERMISSION), 0));
+                mUsbManager.requestPermission(
+                        device, PendingIntent.getBroadcast(
+                                        context, 0, new Intent(ACTION_USB_PERMISSION), 0));
                 mRequestedDevices.add(device);
                 break;
             }
@@ -164,7 +164,7 @@ class UsbMidiDeviceFactoryAndroid {
      * @param device a USB device
      */
     private void onUsbDeviceDetached(UsbDevice device) {
-        for (UsbDevice usbDevice: mRequestedDevices) {
+        for (UsbDevice usbDevice : mRequestedDevices) {
             if (usbDevice.getDeviceId() == device.getDeviceId()) {
                 mRequestedDevices.remove(usbDevice);
                 break;
@@ -214,7 +214,7 @@ class UsbMidiDeviceFactoryAndroid {
         }
 
         if (device != null) {
-            for (UsbMidiDeviceAndroid registered: mDevices) {
+            for (UsbMidiDeviceAndroid registered : mDevices) {
                 if (!registered.isClosed()
                         && registered.getUsbDevice().getDeviceId() == device.getDeviceId()) {
                     // The device is already registered.
diff --git a/media/midi/midi.gyp b/media/midi/midi.gyp
new file mode 100644
index 0000000..554f1a9
--- /dev/null
+++ b/media/midi/midi.gyp
@@ -0,0 +1,235 @@
+# Copyright 2015 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.
+
+{
+  'variables': {
+    'chromium_code': 1,
+    'conditions': [
+      ['(OS=="linux" or OS=="freebsd" or OS=="solaris") and (embedded!=1 or (chromecast==1 and target_arch!="arm"))', {
+        'use_alsa%': 1,
+      }, {
+        'use_alsa%': 0,
+      }],
+    ],
+    # Source files that are used in production code for Android, and in tests
+    # for others.
+    'usb_midi_sources': [
+      'midi_manager_usb.cc',
+      'midi_manager_usb.h',
+      'usb_midi_descriptor_parser.cc',
+      'usb_midi_descriptor_parser.h',
+      'usb_midi_device.h',
+      'usb_midi_input_stream.cc',
+      'usb_midi_input_stream.h',
+      'usb_midi_jack.h',
+      'usb_midi_output_stream.cc',
+      'usb_midi_output_stream.h',
+    ],
+  },
+  'targets': [
+    {
+      # GN version: //media/midi
+      'target_name': 'midi',
+      'type': '<(component)',
+      'dependencies': [
+        '../../base/base.gyp:base',
+      ],
+      'defines': [
+        'MEDIA_IMPLEMENTATION',
+      ],
+      'include_dirs': [
+        '../..',
+      ],
+      'sources': [
+        'midi_manager.cc',
+        'midi_manager.h',
+        'midi_manager_android.cc',
+        'midi_manager_mac.cc',
+        'midi_manager_mac.h',
+        'midi_manager_win.cc',
+        'midi_manager_win.h',
+        'midi_message_queue.cc',
+        'midi_message_queue.h',
+        'midi_message_util.cc',
+        'midi_message_util.h',
+        'midi_port_info.cc',
+        'midi_port_info.h',
+        'midi_scheduler.cc',
+        'midi_scheduler.h',
+        'usb_midi_device_android.cc',
+        'usb_midi_device_android.h',
+        'usb_midi_device_factory_android.cc',
+        'usb_midi_device_factory_android.h',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          '../..',
+        ],
+      },
+      'conditions': [
+        ['use_alsa==1 and use_udev==1', {
+          'dependencies': [
+            '../../crypto/crypto.gyp:crypto',
+            '../../device/udev_linux/udev.gyp:udev_linux',
+          ],
+          'defines': [
+            'USE_ALSA',
+            'USE_UDEV',
+          ],
+          'sources': [
+            'midi_manager_alsa.cc',
+            'midi_manager_alsa.h',
+          ],
+          'link_settings': {
+            'libraries': [
+              '-lasound',
+            ],
+          },
+        }],
+        ['OS=="android"', {
+          'dependencies': [
+            '../../base/base.gyp:base_i18n',
+            'midi_jni_headers',
+            'midi_java',
+          ],
+          'sources': [
+            '<@(usb_midi_sources)',
+            'midi_jni_registrar.cc',
+            'midi_jni_registrar.h',
+          ],
+        }],
+        ['OS=="mac"', {
+          'link_settings': {
+            'libraries': [
+              '$(SDKROOT)/System/Library/Frameworks/CoreAudio.framework',
+              '$(SDKROOT)/System/Library/Frameworks/CoreMIDI.framework',
+            ],
+          },
+        }],
+        ['OS=="win"', {
+          'dependencies': [
+            '../../device/usb/usb.gyp:device_usb',
+          ],
+        }],
+      ],  # conditions
+    },
+    {
+      # GN version: //media/midi:midi_unittests
+      'target_name': 'midi_unittests',
+      'type': '<(gtest_target_type)',
+      'dependencies': [
+        'midi',
+        '../../base/base.gyp:base',
+        '../../base/base.gyp:run_all_unittests',
+        '../../testing/gtest.gyp:gtest',
+      ],
+      'defines': [
+        'MEDIA_IMPLEMENTATION',
+      ],
+      'include_dirs': [
+        '../..',
+      ],
+      'sources': [
+        'midi_manager_unittest.cc',
+        'midi_manager_usb_unittest.cc',
+        'midi_message_queue_unittest.cc',
+        'midi_message_util_unittest.cc',
+        'usb_midi_descriptor_parser_unittest.cc',
+        'usb_midi_input_stream_unittest.cc',
+        'usb_midi_output_stream_unittest.cc',
+      ],
+      'conditions': [
+        ['use_alsa==1 and use_udev==1', {
+          'defines': [
+            'USE_ALSA',
+            'USE_UDEV',
+          ],
+          'sources': [
+            'midi_manager_alsa_unittest.cc',
+          ],
+        }],
+        ['use_x11==1', {
+          'dependencies': [
+            '../../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
+          ],
+        }],
+        ['OS=="android"', {
+          'dependencies': [
+            '../../testing/android/native_test.gyp:native_test_native_code',
+          ],
+        }, {
+          'sources': [
+            '<@(usb_midi_sources)',
+          ],
+        }],
+        ['OS=="mac"', {
+          'sources': [
+            'midi_manager_mac_unittest.cc',
+          ],
+        }],
+      ],
+    },
+  ],
+  'conditions': [
+    ['OS=="android"', {
+      'targets': [
+        {
+          # TODO(GN)
+          'target_name': 'midi_unittests_apk',
+          'type': 'none',
+          'dependencies': [
+            'midi_java',
+            'midi_unittests',
+          ],
+          'variables': {
+            'test_suite_name': 'midi_unittests',
+          },
+          'includes': ['../../build/apk_test.gypi'],
+        },
+        {
+          # GN: //media/midi:midi_java
+          'target_name': 'midi_java',
+          'type': 'none',
+          'dependencies': [
+            '../../base/base.gyp:base',
+          ],
+          'variables': {
+            'java_in_dir': 'java',
+          },
+          'includes': ['../../build/java.gypi' ],
+        },
+        {
+          # GN: //media/midi:midi_jni_headers
+          'target_name': 'midi_jni_headers',
+          'type': 'none',
+          'sources': [
+            'java/src/org/chromium/media/midi/UsbMidiDeviceAndroid.java',
+            'java/src/org/chromium/media/midi/UsbMidiDeviceFactoryAndroid.java',
+          ],
+          'variables': {
+            'jni_gen_package': 'media/midi',
+          },
+          'includes': ['../../build/jni_generator.gypi'],
+        },
+      ],
+    }],
+    ['test_isolation_mode != "noop"', {
+      'targets': [
+        {
+          'target_name': 'midi_unittests_run',
+          'type': 'none',
+          'dependencies': [
+            'midi_unittests',
+          ],
+          'includes': [
+            '../../build/isolate.gypi',
+          ],
+          'sources': [
+            'midi_unittests.isolate',
+          ],
+        },
+      ],
+    }],
+  ],
+}
diff --git a/media/midi/midi_jni_registrar.cc b/media/midi/midi_jni_registrar.cc
new file mode 100644
index 0000000..a0028cd
--- /dev/null
+++ b/media/midi/midi_jni_registrar.cc
@@ -0,0 +1,29 @@
+// Copyright 2015 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.
+
+#include "media/midi/midi_jni_registrar.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_registrar.h"
+#include "base/basictypes.h"
+
+#include "media/midi/usb_midi_device_android.h"
+#include "media/midi/usb_midi_device_factory_android.h"
+
+namespace media {
+namespace midi {
+
+static base::android::RegistrationMethod kMediaRegisteredMethods[] = {
+    {"UsbMidiDevice", UsbMidiDeviceAndroid::RegisterUsbMidiDevice},
+    {"UsbMidiDeviceFactory",
+     UsbMidiDeviceFactoryAndroid::RegisterUsbMidiDeviceFactory},
+};
+
+bool RegisterJni(JNIEnv* env) {
+  return base::android::RegisterNativeMethods(
+      env, kMediaRegisteredMethods, arraysize(kMediaRegisteredMethods));
+}
+
+}  // namespace midi
+}  // namespace media
diff --git a/media/midi/midi_jni_registrar.h b/media/midi/midi_jni_registrar.h
new file mode 100644
index 0000000..f981e5c
--- /dev/null
+++ b/media/midi/midi_jni_registrar.h
@@ -0,0 +1,21 @@
+// Copyright 2015 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_MIDI_MIDI_JNI_REGISTRAR_H_
+#define MEDIA_MIDI_MIDI_JNI_REGISTRAR_H_
+
+#include <jni.h>
+
+#include "media/base/media_export.h"
+
+namespace media {
+namespace midi {
+
+// Register all JNI bindings necessary for media/midi.
+MEDIA_EXPORT bool RegisterJni(JNIEnv* env);
+
+}  // namespace midi
+}  // namespace media
+
+#endif  // MEDIA_MIDI_MIDI_JNI_REGISTRAR_H_
diff --git a/media/midi/midi_manager_usb.cc b/media/midi/midi_manager_usb.cc
index 346098c..4548a89 100644
--- a/media/midi/midi_manager_usb.cc
+++ b/media/midi/midi_manager_usb.cc
@@ -74,7 +74,7 @@ void MidiManagerUsb::ReceiveUsbMidiData(UsbMidiDevice* device,
 }
 
 void MidiManagerUsb::OnDeviceAttached(scoped_ptr<UsbMidiDevice> device) {
-  int device_id = devices_.size();
+  int device_id = static_cast<int>(devices_.size());
   devices_.push_back(device.release());
   AddPorts(devices_.back(), device_id);
 }
@@ -86,13 +86,13 @@ void MidiManagerUsb::OnDeviceDetached(size_t index) {
   UsbMidiDevice* device = devices_[index];
   for (size_t i = 0; i < output_streams_.size(); ++i) {
     if (output_streams_[i]->jack().device == device) {
-      SetOutputPortState(i, MIDI_PORT_DISCONNECTED);
+      SetOutputPortState(static_cast<uint32>(i), MIDI_PORT_DISCONNECTED);
     }
   }
   const std::vector<UsbMidiJack>& input_jacks = input_stream_->jacks();
   for (size_t i = 0; i < input_jacks.size(); ++i) {
     if (input_jacks[i].device == device) {
-      SetInputPortState(i, MIDI_PORT_DISCONNECTED);
+      SetInputPortState(static_cast<uint32>(i), MIDI_PORT_DISCONNECTED);
     }
   }
 }
@@ -101,7 +101,7 @@ void MidiManagerUsb::OnReceivedData(size_t jack_index,
                                     const uint8* data,
                                     size_t size,
                                     base::TimeTicks time) {
-  ReceiveMidiData(jack_index, data, size, time);
+  ReceiveMidiData(static_cast<uint32>(jack_index), data, size, time);
 }
 
 
@@ -114,7 +114,7 @@ void MidiManagerUsb::OnEnumerateDevicesDone(bool result,
   input_stream_.reset(new UsbMidiInputStream(this));
   devices->swap(devices_);
   for (size_t i = 0; i < devices_.size(); ++i) {
-    if (!AddPorts(devices_[i], i)) {
+    if (!AddPorts(devices_[i], static_cast<int>(i))) {
       initialize_callback_.Run(MIDI_INITIALIZATION_ERROR);
       return;
     }
diff --git a/media/midi/midi_manager_win.cc b/media/midi/midi_manager_win.cc
index 5937278..eb729ea 100644
--- a/media/midi/midi_manager_win.cc
+++ b/media/midi/midi_manager_win.cc
@@ -101,7 +101,7 @@ ScopedMIDIHDR CreateMIDIHDR(size_t size) {
   ScopedMIDIHDR header(new MIDIHDR);
   ZeroMemory(header.get(), sizeof(*header));
   header->lpData = new char[size];
-  header->dwBufferLength = size;
+  header->dwBufferLength = static_cast<DWORD>(size);
   return header.Pass();
 }
 
@@ -619,7 +619,7 @@ class MidiServiceWinImpl : public MidiServiceWin,
       base::AutoLock auto_lock(input_ports_lock_);
       const auto it = unused_input_ports_.find(state_device_info);
       if (it == unused_input_ports_.end()) {
-        port_number = input_ports_.size();
+        port_number = static_cast<uint32>(input_ports_.size());
         add_new_port = true;
         input_ports_.push_back(nullptr);
         input_ports_ages_.push_back(0);
@@ -800,7 +800,7 @@ class MidiServiceWinImpl : public MidiServiceWin,
       base::AutoLock auto_lock(output_ports_lock_);
       const auto it = unused_output_ports_.find(state_device_info);
       if (it == unused_output_ports_.end()) {
-        port_number = output_ports_.size();
+        port_number = static_cast<uint32>(output_ports_.size());
         add_new_port = true;
         output_ports_.push_back(nullptr);
         output_ports_ages_.push_back(0);
diff --git a/media/midi/midi_scheduler.h b/media/midi/midi_scheduler.h
index 73c8bc6..452328b 100644
--- a/media/midi/midi_scheduler.h
+++ b/media/midi/midi_scheduler.h
@@ -7,6 +7,7 @@
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
+#include "media/base/media_export.h"
 
 namespace media {
 
@@ -14,7 +15,7 @@ class MidiManager;
 class MidiManagerClient;
 
 // TODO(crbug.com/467442): Make tasks cancelable per client.
-class MidiScheduler final {
+class MEDIA_EXPORT MidiScheduler final {
  public:
   explicit MidiScheduler(MidiManager* manager);
   ~MidiScheduler();
diff --git a/media/midi/midi_unittests.isolate b/media/midi/midi_unittests.isolate
new file mode 100644
index 0000000..dca0d35
--- /dev/null
+++ b/media/midi/midi_unittests.isolate
@@ -0,0 +1,63 @@
+# Copyright 2015 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.
+{
+  'includes': [
+    '../../base/base.isolate',
+  ],
+  'conditions': [
+    ['use_x11==0', {
+      'variables': {
+        'command': [
+          '../../testing/test_env.py',
+          '<(PRODUCT_DIR)/midi_unittests<(EXECUTABLE_SUFFIX)',
+          '--brave-new-test-launcher',
+          '--test-launcher-bot-mode',
+          '--asan=<(asan)',
+          '--msan=<(msan)',
+          '--tsan=<(tsan)',
+        ],
+      },
+    }],
+    ['use_x11==1', {
+      'variables': {
+        'command': [
+          '../../testing/xvfb.py',
+          '<(PRODUCT_DIR)',
+          '<(PRODUCT_DIR)/midi_unittests',
+          '--brave-new-test-launcher',
+          '--test-launcher-bot-mode',
+          '--asan=<(asan)',
+          '--msan=<(msan)',
+          '--tsan=<(tsan)',
+        ],
+        'files': [
+          '../../testing/xvfb.py',
+          '<(PRODUCT_DIR)/xdisplaycheck',
+        ],
+      },
+    }],
+    ['OS=="linux" or OS=="mac" or OS=="win"', {
+      'variables': {
+        'files': [
+          '../../testing/test_env.py',
+          '<(PRODUCT_DIR)/midi_unittests<(EXECUTABLE_SUFFIX)',
+        ],
+      },
+    }],
+    ['OS=="mac" and asan==1 and fastbuild==0', {
+      'variables': {
+        'files': [
+          '<(PRODUCT_DIR)/midi_unittests.dSYM/',
+        ],
+      },
+    }],
+    ['OS=="win" and (fastbuild==0 or fastbuild==1)', {
+      'variables': {
+        'files': [
+          '<(PRODUCT_DIR)/midi_unittests.exe.pdb',
+        ],
+      },
+    }],
+  ],
+}
diff --git a/media/midi/usb_midi_device_android.cc b/media/midi/usb_midi_device_android.cc
index f62eb86..640ef22 100644
--- a/media/midi/usb_midi_device_android.cc
+++ b/media/midi/usb_midi_device_android.cc
@@ -20,8 +20,8 @@ UsbMidiDeviceAndroid::UsbMidiDeviceAndroid(ObjectRef raw_device,
                                            UsbMidiDeviceDelegate* delegate)
     : raw_device_(raw_device), delegate_(delegate) {
   JNIEnv* env = base::android::AttachCurrentThread();
-  Java_UsbMidiDeviceAndroid_registerSelf(
-      env, raw_device_.obj(), reinterpret_cast<jlong>(this));
+  midi::Java_UsbMidiDeviceAndroid_registerSelf(env, raw_device_.obj(),
+                                               reinterpret_cast<jlong>(this));
 
   GetDescriptorsInternal();
   InitDeviceInfo();
@@ -29,7 +29,7 @@ UsbMidiDeviceAndroid::UsbMidiDeviceAndroid(ObjectRef raw_device,
 
 UsbMidiDeviceAndroid::~UsbMidiDeviceAndroid() {
   JNIEnv* env = base::android::AttachCurrentThread();
-  Java_UsbMidiDeviceAndroid_close(env, raw_device_.obj());
+  midi::Java_UsbMidiDeviceAndroid_close(env, raw_device_.obj());
 }
 
 std::vector<uint8> UsbMidiDeviceAndroid::GetDescriptors() {
@@ -55,8 +55,8 @@ void UsbMidiDeviceAndroid::Send(int endpoint_number,
   ScopedJavaLocalRef<jbyteArray> data_to_pass =
       base::android::ToJavaByteArray(env, head, data.size());
 
-  Java_UsbMidiDeviceAndroid_send(
-      env, raw_device_.obj(), endpoint_number, data_to_pass.obj());
+  midi::Java_UsbMidiDeviceAndroid_send(env, raw_device_.obj(), endpoint_number,
+                                       data_to_pass.obj());
 }
 
 void UsbMidiDeviceAndroid::OnData(JNIEnv* env,
@@ -72,13 +72,13 @@ void UsbMidiDeviceAndroid::OnData(JNIEnv* env,
 }
 
 bool UsbMidiDeviceAndroid::RegisterUsbMidiDevice(JNIEnv* env) {
-  return RegisterNativesImpl(env);
+  return midi::RegisterNativesImpl(env);
 }
 
 void UsbMidiDeviceAndroid::GetDescriptorsInternal() {
   JNIEnv* env = base::android::AttachCurrentThread();
   base::android::ScopedJavaLocalRef<jbyteArray> descriptors =
-      Java_UsbMidiDeviceAndroid_getDescriptors(env, raw_device_.obj());
+      midi::Java_UsbMidiDeviceAndroid_getDescriptors(env, raw_device_.obj());
 
   base::android::JavaByteArrayToByteVector(env, descriptors.obj(),
                                            &descriptors_);
@@ -111,8 +111,8 @@ void UsbMidiDeviceAndroid::InitDeviceInfo() {
 std::vector<uint8> UsbMidiDeviceAndroid::GetStringDescriptor(int index) {
   JNIEnv* env = base::android::AttachCurrentThread();
   base::android::ScopedJavaLocalRef<jbyteArray> descriptors =
-      Java_UsbMidiDeviceAndroid_getStringDescriptor(env, raw_device_.obj(),
-                                                    index);
+      midi::Java_UsbMidiDeviceAndroid_getStringDescriptor(
+          env, raw_device_.obj(), index);
 
   std::vector<uint8> ret;
   base::android::JavaByteArrayToByteVector(env, descriptors.obj(), &ret);
diff --git a/media/midi/usb_midi_device_factory_android.cc b/media/midi/usb_midi_device_factory_android.cc
index 6302572..f066428 100644
--- a/media/midi/usb_midi_device_factory_android.cc
+++ b/media/midi/usb_midi_device_factory_android.cc
@@ -30,7 +30,7 @@ UsbMidiDeviceFactoryAndroid::UsbMidiDeviceFactoryAndroid() : delegate_(NULL) {}
 UsbMidiDeviceFactoryAndroid::~UsbMidiDeviceFactoryAndroid() {
   JNIEnv* env = base::android::AttachCurrentThread();
   if (!raw_factory_.is_null())
-    Java_UsbMidiDeviceFactoryAndroid_close(
+    midi::Java_UsbMidiDeviceFactoryAndroid_close(
         env, raw_factory_.obj(), base::android::GetApplicationContext());
 }
 
@@ -40,13 +40,13 @@ void UsbMidiDeviceFactoryAndroid::EnumerateDevices(
   DCHECK(!delegate_);
   JNIEnv* env = base::android::AttachCurrentThread();
   uintptr_t pointer = reinterpret_cast<uintptr_t>(this);
-  raw_factory_.Reset(Java_UsbMidiDeviceFactoryAndroid_create(
+  raw_factory_.Reset(midi::Java_UsbMidiDeviceFactoryAndroid_create(
       env, base::android::GetApplicationContext(), pointer));
 
   delegate_ = delegate;
   callback_ = callback;
 
-  if (Java_UsbMidiDeviceFactoryAndroid_enumerateDevices(
+  if (midi::Java_UsbMidiDeviceFactoryAndroid_enumerateDevices(
           env, raw_factory_.obj(), base::android::GetApplicationContext())) {
     // Asynchronous operation.
     return;
@@ -92,7 +92,7 @@ void UsbMidiDeviceFactoryAndroid::OnUsbMidiDeviceDetached(
 }
 
 bool UsbMidiDeviceFactoryAndroid::RegisterUsbMidiDeviceFactory(JNIEnv* env) {
-  return RegisterNativesImpl(env);
+  return midi::RegisterNativesImpl(env);
 }
 
 }  // namespace media
diff --git a/media/midi/usb_midi_output_stream.cc b/media/midi/usb_midi_output_stream.cc
index 2f32897..8f1af70 100644
--- a/media/midi/usb_midi_output_stream.cc
+++ b/media/midi/usb_midi_output_stream.cc
@@ -98,7 +98,7 @@ bool UsbMidiOutputStream::PushSysExMessage(const std::vector<uint8>& data,
     message[message_size] = byte;
     ++message_size;
     if (byte == kEndOfSysExByte) {
-      uint8 code_index = message_size + 0x4;
+      uint8 code_index = static_cast<uint8>(message_size) + 0x4;
       DCHECK(code_index == 0x5 || code_index == 0x6 || code_index == 0x7);
       data_to_send->push_back((jack_.cable_number << 4) | code_index);
       data_to_send->insert(data_to_send->end(),