Move and rename TaskTimeTracker to public interface exposed to WebThread, use in WebPerf Agent.

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

Index: third_party/WebKit/Source/core/inspector/InspectorWebPerfAgent.cpp
diff --git a/third_party/WebKit/Source/core/inspector/InspectorWebPerfAgent.cpp b/third_party/WebKit/Source/core/inspector/InspectorWebPerfAgent.cpp
index 6f99692e698373030d5c0de4453b72f971312f91..e2da5e402dd1fd11e7a59445e50ae3628471e238 100644
--- a/third_party/WebKit/Source/core/inspector/InspectorWebPerfAgent.cpp
+++ b/third_party/WebKit/Source/core/inspector/InspectorWebPerfAgent.cpp
@@ -4,18 +4,33 @@
 
 #include "core/inspector/InspectorWebPerfAgent.h"
 
+#include "core/InstrumentingAgents.h"
 #include "core/frame/LocalFrame.h"
 #include "core/inspector/InspectedFrames.h"
+#include "public/platform/Platform.h"
 
 namespace blink {
 
+// Register InspectorAgent to begin observing LongTaskTiming
+void InspectorWebPerfAgent::enableInstrumentation(LocalFrame* frame)
+{
+    if (frame->isLocalRoot()) {
+        InspectorWebPerfAgent* agent = new InspectorWebPerfAgent(
+            InspectedFrames::create(frame));
+        frame->instrumentingAgents()->addInspectorWebPerfAgent(
+            agent);
+    }
+}
+
 InspectorWebPerfAgent::InspectorWebPerfAgent(InspectedFrames* inspectedFrames)
     : m_inspectedFrames(inspectedFrames)
 {
+    Platform::current()->currentThread()->addTaskTimeObserver(this);
 }
 
 InspectorWebPerfAgent::~InspectorWebPerfAgent()
 {
+    Platform::current()->currentThread()->removeTaskTimeObserver(this);
 }
 
 void InspectorWebPerfAgent::willExecuteScript(ExecutionContext* context)
@@ -26,6 +41,18 @@ void InspectorWebPerfAgent::didExecuteScript()
 {
 }
 
+void InspectorWebPerfAgent::willProcessTask()
+{
+}
+
+void InspectorWebPerfAgent::didProcessTask()
+{
+}
+
+void InspectorWebPerfAgent::reportTaskTime(double startTime, double endTime)
+{
+}
+
 DEFINE_TRACE(InspectorWebPerfAgent)
 {
     visitor->trace(m_inspectedFrames);