MidiScheduler binds to task runner of constructing thread

media/midi/midi_manager_android.cc

 // 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.
 
 #include "media/midi/midi_manager_android.h"
 
 #include "base/android/build_info.h"
 #include "base/android/context_utils.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
@@ skipping 17 matching lines @@
           switches::kUseAndroidMidiApi)) {
     return new MidiManagerUsb(std::unique_ptr<UsbMidiDevice::Factory>(
         new UsbMidiDeviceFactoryAndroid));
   }
 
   return new MidiManagerAndroid();
 }
 
 MidiManagerAndroid::MidiManagerAndroid() {}
 
-MidiManagerAndroid::~MidiManagerAndroid() {}
+MidiManagerAndroid::~MidiManagerAndroid() {
+  base::AutoLock auto_lock(scheduler_lock_);
+  CHECK(!scheduler_);
+}
 
 void MidiManagerAndroid::StartInitialization() {
   JNIEnv* env = base::android::AttachCurrentThread();
 
   uintptr_t pointer = reinterpret_cast<uintptr_t>(this);
   raw_manager_.Reset(Java_MidiManagerAndroid_create(
       env, base::android::GetApplicationContext(), pointer));
-  scheduler_.reset(new MidiScheduler(this));
+
+  {
+    base::AutoLock auto_lock(scheduler_lock_);
+    scheduler_.reset(new MidiScheduler(this));
+  }
+
   Java_MidiManagerAndroid_initialize(env, raw_manager_);
 }
 
+void MidiManagerAndroid::Finalize() {
+  // Destruct MidiScheduler on Chrome_IOThread.
+  base::AutoLock auto_lock(scheduler_lock_);
+  scheduler_.reset();
+}
+
 void MidiManagerAndroid::DispatchSendMidiData(MidiManagerClient* client,
                                               uint32_t port_index,
                                               const std::vector<uint8_t>& data,
                                               double timestamp) {
   if (port_index >= all_output_ports_.size()) {
     // |port_index| is provided by a renderer so we can't believe that it is
     // in the valid range.
     return;
   }
   DCHECK_EQ(output_ports().size(), all_output_ports_.size());
@@ skipping 101 matching lines @@
   }
   devices_.push_back(device.release());
 }
 
 bool MidiManagerAndroid::Register(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace midi
 }  // namespace media