Use monotonicallyIncreasingTime for Timeline timestamps

Source/core/inspector/InspectorTimelineAgent.h

Index: Source/core/inspector/InspectorTimelineAgent.h
diff --git a/Source/core/inspector/InspectorTimelineAgent.h b/Source/core/inspector/InspectorTimelineAgent.h
index 39909d33ef8e20b07124e96e8be36e385dc82ece..41888700eb8d5a13871a0fa374fa0344d36207a3 100644
--- a/Source/core/inspector/InspectorTimelineAgent.h
+++ b/Source/core/inspector/InspectorTimelineAgent.h
@@ -88,19 +88,6 @@ class XMLHttpRequest;
 
 typedef String ErrorString;
 
-class TimelineTimeConverter {
-public:
-    TimelineTimeConverter()
-        : m_startOffset(0)
-    {
-    }
-    double fromMonotonicallyIncreasingTime(double time) const  { return (time - m_startOffset) * 1000.0; }
-    void reset();
-
-private:
-    double m_startOffset;
-};
-
 class InspectorTimelineAgent FINAL
     : public TraceEventTarget<InspectorTimelineAgent>
     , public InspectorBaseAgent<InspectorTimelineAgent>
@@ -295,6 +282,7 @@ private:
     void releaseNodeIds();
 
     double timestamp();
+    double toTimelineTimestamp(double);
 
     FrameHost* frameHost() const;
 
@@ -313,7 +301,6 @@ private:
     int m_id;
     unsigned long long m_layerTreeId;
 
-    TimelineTimeConverter m_timeConverter;
     int m_maxCallStackDepth;
 
     Vector<TimelineRecordEntry> m_recordStack;