Pass DOMWinow to PerformanceLongTaskTiming for attribution

third_party/WebKit/Source/core/timing/PerformanceLongTaskTiming.cpp

Index: third_party/WebKit/Source/core/timing/PerformanceLongTaskTiming.cpp
diff --git a/third_party/WebKit/Source/core/timing/PerformanceLongTaskTiming.cpp b/third_party/WebKit/Source/core/timing/PerformanceLongTaskTiming.cpp
index 3d7dda02e67cf30c8a68801c89cdef669175b9d1..d8d427de1fab5427d71019cf3f8bbee8719b193d 100644
--- a/third_party/WebKit/Source/core/timing/PerformanceLongTaskTiming.cpp
+++ b/third_party/WebKit/Source/core/timing/PerformanceLongTaskTiming.cpp
@@ -4,16 +4,31 @@
 
 #include "core/timing/PerformanceLongTaskTiming.h"
 
+#include "bindings/core/v8/V8ObjectBuilder.h"
+#include "core/frame/DOMWindow.h"
+
 namespace blink {
 
 PerformanceLongTaskTiming::PerformanceLongTaskTiming(double startTime,
                                                      double endTime,
-                                                     String frameContextUrl)
-    : PerformanceEntry(frameContextUrl, "longtask", startTime, endTime) {}
+                                                     String name,
+                                                     DOMWindow* culpritWindow)
+    : PerformanceEntry(name, "longtask", startTime, endTime),
+      m_culpritWindow(*culpritWindow) {}
 
 PerformanceLongTaskTiming::~PerformanceLongTaskTiming() {}
 
+DOMWindow* PerformanceLongTaskTiming::culpritWindow() const {
+  return m_culpritWindow.get();
+}
+
+void PerformanceLongTaskTiming::buildJSONValue(V8ObjectBuilder& builder) const {
+  PerformanceEntry::buildJSONValue(builder);
+  builder.add("culpritWindow", culpritWindow());

[caseq, 2016/10/05 00:22:18]

This looks suspicious to me -- we can't really serialize the window as a JSON.
Let's just remove this?

[panicker, 2016/10/05 01:02:18]

Done.

+}
+
 DEFINE_TRACE(PerformanceLongTaskTiming) {
+  visitor->trace(m_culpritWindow);
   PerformanceEntry::trace(visitor);
 }