[Bindings] Cache handles for dictionary keys on V8PerIsolateData.

third_party/WebKit/Source/bindings/templates/dictionary_v8.cpp.tmpl

Index: third_party/WebKit/Source/bindings/templates/dictionary_v8.cpp.tmpl
diff --git a/third_party/WebKit/Source/bindings/templates/dictionary_v8.cpp.tmpl b/third_party/WebKit/Source/bindings/templates/dictionary_v8.cpp.tmpl
index bf6096e026e0b8dfe7d1f006a56f0b80a2891bb4..903e0a9aa0e02215cb18d478772404e53a8673b2 100644
--- a/third_party/WebKit/Source/bindings/templates/dictionary_v8.cpp.tmpl
+++ b/third_party/WebKit/Source/bindings/templates/dictionary_v8.cpp.tmpl
@@ -10,6 +10,18 @@
 
 namespace blink {
 
+{% if members %}
+static const v8::Eternal<v8::Name>* eternal{{v8_class}}Keys(v8::Isolate* isolate) {
+  static const char* const kKeys[] = {
+    {% for member in members %}
+    "{{member.name}}",
+    {% endfor %}
+  };
+  return V8PerIsolateData::from(isolate)->findOrCreateKeys(
+      kKeys, kKeys, WTF_ARRAY_LENGTH(kKeys));
+}
+{% endif %}
+
 {% from 'utilities.cpp.tmpl' import v8_value_to_local_cpp_value %}
 void {{v8_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value> v8Value, {{cpp_class}}& impl, ExceptionState& exceptionState) {
   if (isUndefinedOrNull(v8Value)) {
@@ -38,12 +50,14 @@ void {{v8_class}}::toImpl(v8::Isolate* isolate, v8::Local<v8::Value> v8Value, {{
   {% endif %}
   {# Declare local variables only when the dictionary has members to avoid unused variable warnings. #}
   {% if members %}
+  const v8::Eternal<v8::Name>* keys = eternal{{v8_class}}Keys(isolate);
   v8::TryCatch block(isolate);
+  v8::Local<v8::Context> context = isolate->GetCurrentContext();
   {% endif %}
   {% for member in members %}
   {% filter runtime_enabled(member.runtime_enabled_feature_name) %}
   v8::Local<v8::Value> {{member.name}}Value;
-  if (!v8Object->Get(isolate->GetCurrentContext(), v8AtomicString(isolate, "{{member.name}}")).ToLocal(&{{member.name}}Value)) {
+  if (!v8Object->Get(context, keys[{{loop.index0}}].Get(isolate)).ToLocal(&{{member.name}}Value)) {
     exceptionState.rethrowV8Exception(block.Exception());
     return;
   }
@@ -99,20 +113,24 @@ bool toV8{{cpp_class}}(const {{cpp_class}}& impl, v8::Local<v8::Object> dictiona
     return false;
 
   {% endif %}
+  {% if members %}
+  const v8::Eternal<v8::Name>* keys = eternal{{v8_class}}Keys(isolate);
+  v8::Local<v8::Context> context = isolate->GetCurrentContext();
+  {% endif %}
   {% for member in members %}
   if (impl.{{member.has_method_name}}()) {
     {% if member.is_object %}
     DCHECK(impl.{{member.getter_name}}().isObject());
     {% endif %}
-    if (!v8CallBoolean(dictionary->CreateDataProperty(isolate->GetCurrentContext(), v8AtomicString(isolate, "{{member.name}}"), {{member.cpp_value_to_v8_value}})))
+    if (!v8CallBoolean(dictionary->CreateDataProperty(context, keys[{{loop.index0}}].Get(isolate), {{member.cpp_value_to_v8_value}})))
       return false;
   {% if member.v8_default_value %}
   } else {
-    if (!v8CallBoolean(dictionary->CreateDataProperty(isolate->GetCurrentContext(), v8AtomicString(isolate, "{{member.name}}"), {{member.v8_default_value}})))
+    if (!v8CallBoolean(dictionary->CreateDataProperty(context, keys[{{loop.index0}}].Get(isolate), {{member.v8_default_value}})))
       return false;
   {% elif member.is_nullable %}
   } else {
-    if (!v8CallBoolean(dictionary->CreateDataProperty(isolate->GetCurrentContext(), v8AtomicString(isolate, "{{member.name}}"), v8::Null(isolate))))
+    if (!v8CallBoolean(dictionary->CreateDataProperty(context, keys[{{loop.index0}}].Get(isolate), v8::Null(isolate))))
       return false;
   {% elif member.is_required %}
   } else {