[Bindings] Cache handles for dictionary keys on V8PerIsolateData.

third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp b/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp
index b01fec9de8d90057ffd32f26320064480c86195b..b8df86693089ad7e3dc067cd285907d9eac1f44e 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp
@@ -29,6 +29,7 @@
 
 #include "bindings/core/v8/DOMDataStore.h"
 #include "bindings/core/v8/ScriptSourceCode.h"
+#include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8HiddenValue.h"
 #include "bindings/core/v8/V8ObjectConstructor.h"
 #include "bindings/core/v8/V8PrivateProperty.h"
@@ -189,6 +190,27 @@ void V8PerIsolateData::setInterfaceTemplate(
   map.insert(key, v8::Eternal<v8::FunctionTemplate>(isolate(), value));
 }
 
+const v8::Eternal<v8::Name>* V8PerIsolateData::findOrCreateKeys(
+    const void* lookupKey,
+    const char* const keys[],
+    size_t keyCount) {
+  auto it = m_keyMap.find(lookupKey);
+  Vector<v8::Eternal<v8::Name>>* vector = nullptr;
+  if (UNLIKELY(it == m_keyMap.end())) {
+    v8::Isolate* isolate = this->isolate();
+    Vector<v8::Eternal<v8::Name>> newVector(keyCount);
+    std::transform(
+        keys, keys + keyCount, newVector.begin(), [isolate](const char* key) {
+          return v8::Eternal<v8::Name>(isolate, v8AtomicString(isolate, key));
+        });
+    vector = &m_keyMap.set(lookupKey, std::move(newVector)).storedValue->value;
+  } else {
+    vector = &it->value;
+  }
+  DCHECK_EQ(vector->size(), keyCount);
+  return vector->data();
+}
+
 v8::Local<v8::Context> V8PerIsolateData::ensureScriptRegexpContext() {
   if (!m_scriptRegexpScriptState) {
     LEAK_SANITIZER_DISABLED_SCOPE;