Revert of arc: enable Android tracing from chrome://tracing in dev mode

components/arc/arc_bridge_service.h

Index: components/arc/arc_bridge_service.h
diff --git a/components/arc/arc_bridge_service.h b/components/arc/arc_bridge_service.h
index a7377f9504a323a94b2345dc6893346fb2a3518c..60abe9d52dc3dcc9bf648fe13476f18ad6a53d45 100644
--- a/components/arc/arc_bridge_service.h
+++ b/components/arc/arc_bridge_service.h
@@ -36,7 +36,6 @@
 class PrintInstance;
 class ProcessInstance;
 class StorageManagerInstance;
-class TracingInstance;
 class TtsInstance;
 class VideoInstance;
 class WallpaperInstance;
@@ -90,7 +89,6 @@
   InstanceHolder<mojom::StorageManagerInstance>* storage_manager() {
     return &storage_manager_;
   }
-  InstanceHolder<mojom::TracingInstance>* tracing() { return &tracing_; }
   InstanceHolder<mojom::TtsInstance>* tts() { return &tts_; }
   InstanceHolder<mojom::VideoInstance>* video() { return &video_; }
   InstanceHolder<mojom::WallpaperInstance>* wallpaper() { return &wallpaper_; }
@@ -118,7 +116,6 @@
   InstanceHolder<mojom::PrintInstance> print_;
   InstanceHolder<mojom::ProcessInstance> process_;
   InstanceHolder<mojom::StorageManagerInstance> storage_manager_;
-  InstanceHolder<mojom::TracingInstance> tracing_;
   InstanceHolder<mojom::TtsInstance> tts_;
   InstanceHolder<mojom::VideoInstance> video_;
   InstanceHolder<mojom::WallpaperInstance> wallpaper_;