Adding flow traces for blink scheduler events

Source/platform/scheduler/TracedTask.cpp

Index: Source/platform/scheduler/TracedTask.cpp
diff --git a/Source/platform/scheduler/TracedTask.cpp b/Source/platform/scheduler/TracedTask.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..06338ec035e44556735de64ccf96947c13d6d18a
--- /dev/null
+++ b/Source/platform/scheduler/TracedTask.cpp
@@ -0,0 +1,34 @@
+// Copyright 2014 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.
+
+#include "config.h"
+#include "platform/scheduler/TracedTask.h"
+
+#include "platform/TraceEvent.h"
+
+namespace blink {
+
+void TracedTask::run() const
+{
+    TRACE_EVENT_FLOW_END0("blink", m_traceName, TRACE_ID_MANGLE(m_flowTraceID));
+
+    TRACE_EVENT2("blink", m_traceName,
+        "src_file", m_location.fileName(),
+        "src_func", m_location.functionName());
+
+    m_task();
+}
+
+TracedTask::TracedTask(const Task& task, const TraceLocation& location, const char* traceName, int flowTraceID)
+    : m_flowTraceID(static_cast<uint64_t>(flowTraceID))
+    , m_task(task)
+    , m_location(location)
+    , m_traceName(traceName)
+{
+    TRACE_EVENT_FLOW_BEGIN2("blink", m_traceName, TRACE_ID_MANGLE(m_flowTraceID),
+        "src_file", m_location.fileName(),
+        "src_func", m_location.functionName());
+}
+
+} // namespace blink