First version of PerformanceObserver

Source/core/inspector/AsyncCallTracker.h

Index: Source/core/inspector/AsyncCallTracker.h
diff --git a/Source/core/inspector/AsyncCallTracker.h b/Source/core/inspector/AsyncCallTracker.h
index a28f69bcb20e4811ad39428af276a4f0bfd08b94..453dfbedb1ea11a523e41d11d080293e51f2f41b 100644
--- a/Source/core/inspector/AsyncCallTracker.h
+++ b/Source/core/inspector/AsyncCallTracker.h
@@ -50,6 +50,7 @@ class HTTPHeaderMap;
 class InspectorDebuggerAgent;
 class KURL;
 class MutationObserver;
+class PerformanceObserver;
 class ThreadableLoaderClient;
 class XMLHttpRequest;
 
@@ -87,6 +88,11 @@ public:
     void willDeliverMutationRecords(ExecutionContext*, MutationObserver*);
     void didDeliverMutationRecords() { didFireAsyncCall(); }
 
+    void didEnqueuePerformanceObserverEntries(ExecutionContext*, PerformanceObserver*);
+    void didClearAllPerformanceObservations(ExecutionContext*, PerformanceObserver*);
+    void willDeliverPerformanceObservations(ExecutionContext*, PerformanceObserver*);
+    void didDeliverPerformanceObservations() { didFireAsyncCall(); };
+
     void didPostExecutionContextTask(ExecutionContext*, ExecutionContextTask*);
     void didKillAllExecutionContextTasks(ExecutionContext*);
     void willPerformExecutionContextTask(ExecutionContext*, ExecutionContextTask*);