Expose performance.memory in workers

Source/modules/performance/WorkerPerformance.cpp

Index: Source/modules/performance/WorkerPerformance.cpp
diff --git a/Source/modules/performance/WorkerPerformance.cpp b/Source/modules/performance/WorkerPerformance.cpp
index 6010610195b6070c497a0cd72edbcffda5dec516..5f18d01067769a04e47883232a29ae72956f0e8d 100644
--- a/Source/modules/performance/WorkerPerformance.cpp
+++ b/Source/modules/performance/WorkerPerformance.cpp
@@ -31,6 +31,7 @@
 #include "config.h"
 #include "modules/performance/WorkerPerformance.h"
 
+#include "core/timing/MemoryInfo.h"
 #include "core/workers/DedicatedWorkerGlobalScope.h"
 #include "core/workers/WorkerGlobalScope.h"
 #include "wtf/CurrentTime.h"
@@ -56,4 +57,9 @@ double WorkerPerformance::now(ExecutionContext* context) const
     return 1000.0 * (monotonicallyIncreasingTime() - workerGlobalScope->timeOrigin());
 }
 
+PassRefPtr<MemoryInfo> WorkerPerformance::memory(ExecutionContext* context) const
+{
+    return MemoryInfo::create(context);
+}
+
 } // namespace WebCore