Web MIDI: add an unit test to check MidiManager instantiation

media/midi/midi_manager_usb_unittest.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_usb.h"
 
 #include <string>
 
+#include "base/message_loop/message_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/time/time.h"
 #include "media/midi/usb_midi_device.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media {
 
 namespace {
 
 template<typename T, size_t N>
@@ skipping 115 matching lines @@
   void CallCompleteInitialization(MidiResult result) {
     CompleteInitialization(result);
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MidiManagerUsbForTesting);
 };
 
 class MidiManagerUsbTest : public ::testing::Test {
  public:
-  MidiManagerUsbTest() {
+  MidiManagerUsbTest() : message_loop_(new base::MessageLoop) {
     scoped_ptr<TestUsbMidiDeviceFactory> factory(new TestUsbMidiDeviceFactory);
     factory_ = factory.get();
     manager_.reset(
         new MidiManagerUsbForTesting(factory.PassAs<UsbMidiDevice::Factory>()));
   }
   virtual ~MidiManagerUsbTest() {
     std::string leftover_logs = logger_.TakeLog();
     if (!leftover_logs.empty()) {
       ADD_FAILURE() << "Log should be empty: " << leftover_logs;
     }
@@ skipping 17 matching lines @@
     return client_->result_;
   }
 
   scoped_ptr<MidiManagerUsbForTesting> manager_;
   scoped_ptr<FakeMidiManagerClient> client_;
   // Owned by manager_.
   TestUsbMidiDeviceFactory* factory_;
   Logger logger_;
 
  private:
+  scoped_ptr<base::MessageLoop> message_loop_;
+
   DISALLOW_COPY_AND_ASSIGN(MidiManagerUsbTest);
 };
 
 
 TEST_F(MidiManagerUsbTest, Initialize) {
   scoped_ptr<FakeUsbMidiDevice> device(new FakeUsbMidiDevice(&logger_));
   uint8 descriptor[] = {
     0x12, 0x01, 0x10, 0x01, 0x00, 0x00, 0x00, 0x08, 0x86, 0x1a,
     0x2d, 0x75, 0x54, 0x02, 0x00, 0x02, 0x00, 0x01, 0x09, 0x02,
     0x75, 0x00, 0x02, 0x01, 0x00, 0x80, 0x30, 0x09, 0x04, 0x00,
@@ skipping 147 matching lines @@
             "data = 0x90 0x45 0x7f\n"
             "MidiManagerClient::ReceiveMidiData port_index = 0 "
             "data = 0xf0 0x00 0x01\n"
             "MidiManagerClient::ReceiveMidiData port_index = 0 data = 0xf7\n",
             logger_.TakeLog());
 }
 
 }  // namespace
 
 }  // namespace media