AudioMirroringManager becomes a global LazyInstance.

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index cd0361ea63ea05cc121bbc052726f6475378a394..0b95dda213f4478e756b8df802d049288b5f7398 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -755,14 +755,14 @@ void RenderProcessHostImpl::CreateMessageFilters() {
   AddFilter(new AudioInputRendererHost(
       audio_manager,
       media_stream_manager,
-      BrowserMainLoop::GetInstance()->audio_mirroring_manager(),
+      AudioMirroringManager::GetInstance(),
       BrowserMainLoop::GetInstance()->user_input_monitor()));
   // The AudioRendererHost needs to be available for lookup, so it's
   // stashed in a member variable.
   audio_renderer_host_ = new AudioRendererHost(
       GetID(),
       audio_manager,
-      BrowserMainLoop::GetInstance()->audio_mirroring_manager(),
+      AudioMirroringManager::GetInstance(),
       media_internals,
       media_stream_manager);
   AddFilter(audio_renderer_host_.get());