Support for tracing app initialization.

mojo/common/tracing_impl.h

Index: mojo/common/tracing_impl.h
diff --git a/mojo/common/tracing_impl.h b/mojo/common/tracing_impl.h
index a996d5c4b281c424e34893d0f0d271408513a015..c798b3e55f994550fce7ab31475450e6bb6815e2 100644
--- a/mojo/common/tracing_impl.h
+++ b/mojo/common/tracing_impl.h
@@ -6,6 +6,7 @@
 #define MOJO_COMMON_TRACING_IMPL_H_
 
 #include "base/macros.h"
+#include "mojo/common/trace_provider_impl.h"
 #include "mojo/public/cpp/application/interface_factory.h"
 #include "mojo/services/tracing/public/interfaces/tracing.mojom.h"
 
@@ -27,6 +28,8 @@ class TracingImpl : public InterfaceFactory<tracing::TraceProvider> {
   void Create(ApplicationConnection* connection,
               InterfaceRequest<tracing::TraceProvider> request) override;
 
+  TraceProviderImpl provider_impl_;
+
   DISALLOW_COPY_AND_ASSIGN(TracingImpl);
 };