Intiialize AudioManager and related class lazily

content/browser/media/webrtc/webrtc_browsertest.cc

 // Copyright (c) 2012 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 "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/threading/platform_thread.h"
 #include "build/build_config.h"
+#include "content/browser/browser_main_loop.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/webrtc_ip_handling_policy.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/content_browser_test_utils.h"
 #include "content/public/test/test_utils.h"
 #include "content/test/webrtc_content_browsertest_base.h"
 #include "media/audio/audio_manager.h"
 #include "media/base/media_switches.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
@@ skipping 13 matching lines @@
  public:
   MAYBE_WebRtcBrowserTest() {}
   ~MAYBE_WebRtcBrowserTest() override {}
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
     WebRtcContentBrowserTest::SetUpCommandLine(command_line);
     // Automatically grant device permission.
     AppendUseFakeUIForMediaStreamFlag();
   }
 
+  void SetUpOnMainThread() override {
+    BrowserMainLoop::GetInstance()->GetMediaStreamManager();
+  }
+
  protected:
   // Convenience function since most peerconnection-call.html tests just load
   // the page, kick off some javascript and wait for the title to change to OK.
   void MakeTypicalPeerConnectionCall(const std::string& javascript) {
     MakeTypicalCall(javascript, "/media/peerconnection-call.html");
   }
 
   // Convenience method for making calls that detect if audio os playing (which
   // has some special prerequisites, such that there needs to be an audio output
   // device on the executing machine).
@@ skipping 269 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(MAYBE_WebRtcBrowserTest, CreateOfferWithOfferOptions) {
   MakeTypicalPeerConnectionCall("testCreateOfferOptions();");
 }
 
 IN_PROC_BROWSER_TEST_F(MAYBE_WebRtcBrowserTest, CallInsideIframe) {
   MakeTypicalPeerConnectionCall("callInsideIframe({video: true, audio:true});");
 }
 
 }  // namespace content