Adding flow traces for blink scheduler events

Source/platform/scheduler/TracedTask.cpp

+// 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_name, TRACE_ID_MANGLE(m_FlowTraceID));
+
+    TRACE_EVENT2("blink", m_name,
+        "src_file", m_location.fileName(),
+        "src_func", m_location.functionName());
+
+    m_task();
+}
+
+TracedTask::TracedTask(const Task& task, const TraceLocation& location, const char* name, int flowTraceID)
+    : m_FlowTraceID(flowTraceID)
+    , m_task(task)
+    , m_location(location)
+    , m_name(name)
+{
+    TRACE_EVENT_FLOW_BEGIN2("blink", m_name, TRACE_ID_MANGLE(m_FlowTraceID),
+        "src_file", m_location.fileName(),
+        "src_func", m_location.functionName());
+}
+
+
+} // namespace blink