DevTools: remove PerformanceMonitor::HandlerCall, migrate to the new scoped probes.

third_party/WebKit/Source/core/inspector/InspectorInstrumentation.cpp

Index: third_party/WebKit/Source/core/inspector/InspectorInstrumentation.cpp
diff --git a/third_party/WebKit/Source/core/inspector/InspectorInstrumentation.cpp b/third_party/WebKit/Source/core/inspector/InspectorInstrumentation.cpp
index 047948087fd0da966275d2905ff87d85a956e29c..a646c324e9127c9edb351b30b1d6c859b4b2cf35 100644
--- a/third_party/WebKit/Source/core/inspector/InspectorInstrumentation.cpp
+++ b/third_party/WebKit/Source/core/inspector/InspectorInstrumentation.cpp
@@ -52,6 +52,23 @@ namespace blink {
 
 namespace probe {
 
+double ProbeBase::captureStartTime() const {
+  if (!m_startTime)
+    m_startTime = monotonicallyIncreasingTime();
+  return m_startTime;
+}
+
+double ProbeBase::captureEndTime() const {
+  if (!m_endTime)
+    m_endTime = monotonicallyIncreasingTime();
+  return m_endTime;
+}
+
+double ProbeBase::duration() const {
+  DCHECK(m_startTime);
+  return captureEndTime() - m_startTime;
+}
+
 AsyncTask::AsyncTask(ExecutionContext* context, void* task)
     : AsyncTask(context, task, true) {}