Convert performance monitor to the subscription model.

third_party/WebKit/Source/core/timing/Performance.h

Index: third_party/WebKit/Source/core/timing/Performance.h
diff --git a/third_party/WebKit/Source/core/timing/Performance.h b/third_party/WebKit/Source/core/timing/Performance.h
index ea5579d589e896fe18300674efdb97df2e7d666e..95bc1fb07652a56e43d13072d7bad3f19417b55d 100644
--- a/third_party/WebKit/Source/core/timing/Performance.h
+++ b/third_party/WebKit/Source/core/timing/Performance.h
@@ -34,6 +34,7 @@
 
 #include "core/CoreExport.h"
 #include "core/frame/DOMWindowProperty.h"
+#include "core/frame/PerformanceMonitor.h"
 #include "core/timing/MemoryInfo.h"
 #include "core/timing/PerformanceBase.h"
 #include "core/timing/PerformanceNavigation.h"
@@ -45,7 +46,8 @@ class ScriptState;
 class ScriptValue;
 
 class CORE_EXPORT Performance final : public PerformanceBase,
-                                      public DOMWindowProperty {
+                                      public DOMWindowProperty,
+                                      public PerformanceMonitor::Client {
   DEFINE_WRAPPERTYPEINFO();
   USING_GARBAGE_COLLECTED_MIXIN(Performance);
   friend class PerformanceTest;
@@ -74,6 +76,15 @@ class CORE_EXPORT Performance final : public PerformanceBase,
   // DOMWindowProperty overrides.
   void frameDestroyed() override;
 
+  static std::pair<String, DOMWindow*> sanitizedAttribution(
+      const HeapHashSet<Member<Frame>>& frames,
+      Frame* observerFrame);
+
+  // PerformanceMonitor::Client implementation.
+  void reportLongTask(double startTime,
+                      double endTime,
+                      const HeapHashSet<Member<Frame>>& contextFrames) override;
+
   mutable Member<PerformanceNavigation> m_navigation;
   mutable Member<PerformanceTiming> m_timing;
 };