Add V8ObjectBuilder helper and use in modules/crypto/

Source/bindings/core/v8/V8ObjectBuilder.cpp

Index: Source/bindings/core/v8/V8ObjectBuilder.cpp
diff --git a/Source/bindings/core/v8/V8ObjectBuilder.cpp b/Source/bindings/core/v8/V8ObjectBuilder.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..30d0a996fcfbcc045c8a71fb9280bf1c0e7b549f
--- /dev/null
+++ b/Source/bindings/core/v8/V8ObjectBuilder.cpp
@@ -0,0 +1,64 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "bindings/core/v8/V8ObjectBuilder.h"
+
+#include "bindings/core/v8/V8Binding.h"
+
+namespace blink {
+
+V8ObjectBuilder::V8ObjectBuilder(v8::Isolate* isolate)
+    : m_isolate(isolate)
+    , m_object(v8::Object::New(isolate))
+{
+}
+
+ScriptValue V8ObjectBuilder::scriptValue() const
+{
+    return ScriptValue(ScriptState::current(m_isolate), m_object);

[haraken, 2015/03/24 14:33:32]

Using ScriptState::current is not nice, since the ScriptState::current depends
on what ScriptState the caller side is using. (For security reasons, it is very
important that we always use a correct ScriptState.)

I think we can pass in ScriptState to the V8ObjectBuilder, cache the ScriptState
on V8ObjectBuilder::m_scriptState, and use it here.

[Jens Widell, 2015/03/24 15:16:29]

Done.

The constructor now takes (and stores) a ScriptState instead of an isolate, and
uses that.

+}
+
+V8ObjectBuilder& V8ObjectBuilder::add(String name, const ScriptValue& value)
+{
+    add(name, value.v8Value());
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::add(String name, const V8ObjectBuilder& value)
+{
+    add(name, value.v8Value());
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::addNull(String name)
+{
+    add(name, v8::Null(m_isolate));
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::addBoolean(String name, bool value)
+{
+    add(name, value ? v8::True(m_isolate) : v8::False(m_isolate));
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::addNumber(String name, double value)
+{
+    add(name, v8::Number::New(m_isolate, value));
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::addString(String name, String value)
+{
+    add(name, v8String(m_isolate, value));
+    return *this;
+}
+
+void V8ObjectBuilder::add(String name, v8::Local<v8::Value> value)
+{
+    m_object->ForceSet(m_isolate->GetCurrentContext(), v8String(m_isolate, name), value);

[haraken, 2015/03/24 14:33:32]

Why do we use ForceSet, not Set?

[haraken, 2015/03/24 14:33:33]

Also we should use m_scriptState->context().

[Jens Widell, 2015/03/24 14:38:40]

Web IDL uses [[DefineOwnProperty]] to describe ECMAScript serializers, for which
I think ForceSet() is a better match than Set(). Please correct me if I'm wrong.

Generally, [[DefineOwnProperty]] is better (than [[Put]]) for all cases where
you simply want to build an object, so hopefully this will work for other
use-cases besides serializers as well.

[Jens Widell, 2015/03/24 15:16:29]

Done.

+}
+
+} // namespace blink