Reland [Tracing] V8 Tracing Controller

include/libplatform/libplatform.h

Index: include/libplatform/libplatform.h
diff --git a/include/libplatform/libplatform.h b/include/libplatform/libplatform.h
index f180b4fe82ef33ee4621c15c55c527ec7aad06db..646c7640da4eabc90492cf47f865d38d3192721f 100644
--- a/include/libplatform/libplatform.h
+++ b/include/libplatform/libplatform.h
@@ -5,6 +5,7 @@
 #ifndef V8_LIBPLATFORM_LIBPLATFORM_H_
 #define V8_LIBPLATFORM_LIBPLATFORM_H_
 
+#include "include/libplatform/v8-tracing.h"
 #include "v8-platform.h"  // NOLINT(build/include)
 
 namespace v8 {
@@ -31,6 +32,14 @@ v8::Platform* CreateDefaultPlatform(int thread_pool_size = 0);
  */
 bool PumpMessageLoop(v8::Platform* platform, v8::Isolate* isolate);
 
+/**
+ * Attempts to set the tracing controller for the given platform.
+ *
+ * The |platform| has to be created using |CreateDefaultPlatform|.
+ */
+void SetTracingController(
+    v8::Platform* platform,
+    v8::platform::tracing::TracingController* tracing_controller);
 
 }  // namespace platform
 }  // namespace v8