Intiialize AudioManager and related class lazily

content/browser/speech/speech_recognition_browsertest.cc

 // Copyright 2013 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 <stddef.h>
 #include <stdint.h>
 #include <string.h>
 
 #include <list>
 #include <memory>
@@ skipping 102 matching lines @@
   void SetUpInProcessBrowserTestFixture() override {
     test_audio_input_controller_factory_.set_delegate(this);
     media::AudioInputController::set_factory_for_testing(
         &test_audio_input_controller_factory_);
     mock_streaming_server_.reset(new MockGoogleStreamingServer(this));
     streaming_server_state_ = kIdle;
   }
 
   void SetUpOnMainThread() override {
     ASSERT_TRUE(SpeechRecognitionManagerImpl::GetInstance());
+    media::AudioManager::StartHangMonitorIfNeeded(
+        BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
     SpeechRecognizerImpl::SetAudioManagerForTesting(
         new media::MockAudioManager(BrowserThread::GetMessageLoopProxyForThread(
             BrowserThread::IO)));
   }
 
   void TearDownOnMainThread() override {
     SpeechRecognizerImpl::SetAudioManagerForTesting(NULL);
   }
 
   void TearDownInProcessBrowserTestFixture() override {
@@ skipping 73 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(SpeechRecognitionBrowserTest, OneShotRecognition) {
   NavigateToURLBlockUntilNavigationsComplete(
       shell(), GetTestUrlFromFragment("oneshot"), 2);
 
   EXPECT_EQ(kClientDisconnected, streaming_server_state());
   EXPECT_EQ("goodresult1", GetPageFragment());
 }
 
 }  // namespace content