Special-case LocalDOMWindow for same-origin access in bindings.

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

Index: third_party/WebKit/Source/core/timing/Performance.cpp
diff --git a/third_party/WebKit/Source/core/timing/Performance.cpp b/third_party/WebKit/Source/core/timing/Performance.cpp
index 1268af74dea9766c2a8dd56aa5082710f4045297..4d4c7aff5290929a4d8e021f12dd9ded83e68b8b 100644
--- a/third_party/WebKit/Source/core/timing/Performance.cpp
+++ b/third_party/WebKit/Source/core/timing/Performance.cpp
@@ -186,7 +186,7 @@ static bool canAccessOrigin(Frame* frame1, Frame* frame2) {
 std::pair<String, DOMWindow*> Performance::sanitizedAttribution(
     ExecutionContext* taskContext,
     bool hasMultipleContexts,
-    Frame* observerFrame) {
+    LocalFrame* observerFrame) {
   if (hasMultipleContexts) {
     // Unable to attribute, multiple script execution contents were involved.
     return std::make_pair(kAmbiguousAttribution, nullptr);
@@ -237,12 +237,13 @@ void Performance::reportLongTask(double startTime,
   std::pair<String, DOMWindow*> attribution = Performance::sanitizedAttribution(
       taskContext, hasMultipleContexts, frame());
   DOMWindow* culpritDomWindow = attribution.second;
-  if (!culpritDomWindow || !culpritDomWindow->document() ||
-      !culpritDomWindow->document()->localOwner()) {
-    addLongTaskTiming(startTime, endTime, attribution.first, "", "", "");
+  if (!culpritDomWindow || !culpritDomWindow->frame() ||
+      !culpritDomWindow->frame()->deprecatedLocalOwner()) {
+    addLongTaskTiming(startTime, endTime, attribution.first, emptyString(),
+                      emptyString(), emptyString());

[dcheng, 2017/02/01 07:22:59]

To avoid constructing three new empty strings.

   } else {
     HTMLFrameOwnerElement* frameOwner =
-        culpritDomWindow->document()->localOwner();
+        culpritDomWindow->frame()->deprecatedLocalOwner();
     addLongTaskTiming(startTime, endTime, attribution.first,
                       getFrameAttribute(frameOwner, HTMLNames::srcAttr, false),
                       getFrameAttribute(frameOwner, HTMLNames::idAttr, false),