Add V8ObjectBuilder helper and use in modules/crypto/

Source/modules/crypto/CryptoResultImpl.cpp

Index: Source/modules/crypto/CryptoResultImpl.cpp
diff --git a/Source/modules/crypto/CryptoResultImpl.cpp b/Source/modules/crypto/CryptoResultImpl.cpp
index b06c814acee8c8b1e16c21c2c3554565823d15d5..cf589e39cfe8a6b420512db823d13967153f4e97 100644
--- a/Source/modules/crypto/CryptoResultImpl.cpp
+++ b/Source/modules/crypto/CryptoResultImpl.cpp
@@ -182,13 +182,10 @@ void CryptoResultImpl::completeWithKeyPair(const WebCryptoKey& publicKey, const
         ScriptState* scriptState = m_resolver->scriptState();
         ScriptState::Scope scope(scriptState);
 
-        Dictionary keyPair = Dictionary::createEmpty(scriptState->isolate());
+        V8ObjectBuilder keyPair(scriptState->isolate());
 
-        v8::Handle<v8::Value> publicKeyValue = toV8(CryptoKey::create(publicKey), scriptState->context()->Global(), scriptState->isolate());
-        v8::Handle<v8::Value> privateKeyValue = toV8(CryptoKey::create(privateKey), scriptState->context()->Global(), scriptState->isolate());
-
-        keyPair.set("publicKey", publicKeyValue);
-        keyPair.set("privateKey", privateKeyValue);
+        keyPair.add("publicKey", ScriptValue::from(scriptState, CryptoKey::create(publicKey)));
+        keyPair.add("privateKey", ScriptValue::from(scriptState, CryptoKey::create(privateKey)));
 
         m_resolver->resolve(keyPair.v8Value());
     }