Add serializers for window.performance.

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

Index: third_party/WebKit/Source/core/timing/MemoryInfo.cpp
diff --git a/third_party/WebKit/Source/core/timing/MemoryInfo.cpp b/third_party/WebKit/Source/core/timing/MemoryInfo.cpp
index be531bb18672fe20aac351af214c15b2fb9e1919..5868fccb8df1004a1a1eac21fc03136a38e9c0e0 100644
--- a/third_party/WebKit/Source/core/timing/MemoryInfo.cpp
+++ b/third_party/WebKit/Source/core/timing/MemoryInfo.cpp
@@ -30,6 +30,8 @@
 
 #include "core/timing/MemoryInfo.h"
 
+#include "bindings/core/v8/ScriptValue.h"
+#include "bindings/core/v8/V8ObjectBuilder.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "platform/RuntimeEnabledFeatures.h"
@@ -145,6 +147,14 @@ size_t quantizeMemorySize(size_t size) {
   return bucketSizeList[numberOfBuckets - 1];
 }
 
+ScriptValue MemoryInfo::toJSONForBinding(ScriptState* scriptState) const {
+  V8ObjectBuilder result(scriptState);
+  result.addNumber("totalJSHeapSize", totalJSHeapSize());
+  result.addNumber("usedJSHeapSize", usedJSHeapSize());
+  result.addNumber("jsHeapSizeLimit", jsHeapSizeLimit());
+  return result.scriptValue();
+}
+
 MemoryInfo::MemoryInfo() {
   if (RuntimeEnabledFeatures::preciseMemoryInfoEnabled())
     getHeapSize(m_info);