LibJS: Add a global "Object" constructor

This patch adds an "Object" constructor to the global object. The only
function it implements so far is Object.getPrototypeOf().

Libraries/LibJS/Runtime/ObjectConstructor.cpp

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/Function.h>
+#include <LibJS/Heap/Heap.h>
+#include <LibJS/Interpreter.h>
+#include <LibJS/Runtime/ObjectConstructor.h>
+
+namespace JS {
+
+ObjectConstructor::ObjectConstructor()
+{
+    put("prototype", interpreter().object_prototype());
+
+    put_native_function("getPrototypeOf", [this](Object*, const Vector<Value>& arguments) -> Value {
+        if (arguments.size() < 1)
+            return {};
+        auto object = arguments[0].to_object(heap());
+        if (interpreter().exception())
+            return {};
+        if (!object.is_object())
+            return {};
+        return object.as_object()->prototype();
+    });
+}
+
+ObjectConstructor::~ObjectConstructor()
+{
+}
+
+Value ObjectConstructor::call(Interpreter& interpreter, const Vector<Value>&)
+{
+    return interpreter.heap().allocate<Object>();
+}
+
+}