Intiialize AudioManager and related class lazily

content/browser/media/webrtc/webrtc_browsertest.cc

Index: content/browser/media/webrtc/webrtc_browsertest.cc
diff --git a/content/browser/media/webrtc/webrtc_browsertest.cc b/content/browser/media/webrtc/webrtc_browsertest.cc
index 9036deea75c1802af6b11fad02bd75d141df6945..ef61f34d907543e5cd16bc621ed2b363768f8dfb 100644
--- a/content/browser/media/webrtc/webrtc_browsertest.cc
+++ b/content/browser/media/webrtc/webrtc_browsertest.cc
@@ -6,6 +6,7 @@
 #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"
@@ -39,6 +40,10 @@ class MAYBE_WebRtcBrowserTest : public WebRtcContentBrowserTest {
     AppendUseFakeUIForMediaStreamFlag();
   }
 
+  void SetUpOnMainThread() override {
+    BrowserMainLoop::GetInstance()->InitializeMediaComponentsIfNeeded();
+  }
+
  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.