Use C++11 features in core/timing

Source/core/timing/Performance.h

Index: Source/core/timing/Performance.h
diff --git a/Source/core/timing/Performance.h b/Source/core/timing/Performance.h
index 0d2e9e6bfe2b9c823d03f70d25d81241e5e3b873..d59c88032e9fd54c72e3ade33f28ae13250df239 100644
--- a/Source/core/timing/Performance.h
+++ b/Source/core/timing/Performance.h
@@ -53,7 +53,7 @@ class ResourceResponse;
 class ResourceTimingInfo;
 class UserTiming;
 
-typedef WillBeHeapVector<RefPtrWillBeMember<PerformanceEntry> > PerformanceEntryVector;
+using PerformanceEntryVector = WillBeHeapVector<RefPtrWillBeMember<PerformanceEntry>>;
 
 class Performance final : public RefCountedWillBeGarbageCollectedFinalized<Performance>, public DOMWindowProperty, public EventTargetWithInlineData {
     DEFINE_WRAPPERTYPEINFO();