[instrumentation] Generalize instrumentation to be used beyond the core layer

third_party/WebKit/Source/platform/instrumentation/PlatformTraceEventsAgent.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PlatformTraceEventsAgent_h
+#define PlatformTraceEventsAgent_h
+
+#include "platform/PlatformExport.h"
+#include "platform/heap/Heap.h"
+#include "platform/instrumentation/tracing/TraceEvent.h"
+
+namespace blink {
+
+namespace probe {
+class PlatformSendRequest;
+}
+
+class PLATFORM_EXPORT PlatformTraceEventsAgent
+    : public GarbageCollected<PlatformTraceEventsAgent> {
+ public:
+  DEFINE_INLINE_TRACE() {}
+
+  void will(const probe::PlatformSendRequest&);
+  void did(const probe::PlatformSendRequest&);
+};
+
+}  // namespace blink
+
+#endif  // !defined(PlatformTraceEventsAgent_h)