mandoline: Add automatic tracing at mojo call sites.

components/html_viewer/global_state.h

Index: components/html_viewer/global_state.h
diff --git a/components/html_viewer/global_state.h b/components/html_viewer/global_state.h
index a7c389476ce21d7d6383e169179aee89db6b318a..c8c95239c29449a36ceb759a0216d63a6defb5dc 100644
--- a/components/html_viewer/global_state.h
+++ b/components/html_viewer/global_state.h
@@ -14,6 +14,7 @@
 #include "components/mus/gles2/raster_thread_helper.h"
 #include "components/mus/public/interfaces/gpu.mojom.h"
 #include "components/resource_provider/public/cpp/resource_loader.h"
+#include "mojo/services/tracing/public/cpp/tracing_impl.h"
 #include "skia/ext/refptr.h"
 #include "ui/gfx/geometry/size.h"
 
@@ -117,6 +118,8 @@ class GlobalState {
   // memory based purging allocator working here.
   DiscardableMemoryAllocator discardable_memory_allocator_;
 
+  mojo::TracingImpl tracing_;
+
   scoped_ptr<scheduler::RendererScheduler> renderer_scheduler_;
   scoped_ptr<BlinkPlatformImpl> blink_platform_;
   base::Thread compositor_thread_;