LibWeb: Add the SubtleCrypto interface

Just some boilerplate code to get started :^)
This adds both the SubtleCrypto constructor to the window object, as
well as the crypto.subtle instance attribute.

Userland/Libraries/LibWeb/Crypto/Crypto.cpp

@@ -8,9 +8,15 @@
 #include <LibJS/Runtime/TypedArray.h>
 #include <LibWeb/Bindings/Wrapper.h>
 #include <LibWeb/Crypto/Crypto.h>
+#include <LibWeb/Crypto/SubtleCrypto.h>
 
 namespace Web::Crypto {
 
+Crypto::Crypto()
+    : m_subtle(SubtleCrypto::create())
+{
+}
+
 DOM::ExceptionOr<JS::Value> Crypto::get_random_values(JS::Value array) const
 {
     // 1. If array is not an Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, BigInt64Array, or BigUint64Array, then throw a TypeMismatchError and terminate the algorithm.

Userland/Libraries/LibWeb/Crypto/Crypto.h

@@ -8,6 +8,7 @@
 
 #include <LibJS/Runtime/Value.h>
 #include <LibWeb/Bindings/Wrappable.h>
+#include <LibWeb/Crypto/SubtleCrypto.h>
 #include <LibWeb/DOM/ExceptionOr.h>
 
 namespace Web::Crypto {
@@ -23,10 +24,14 @@ public:
         return adopt_ref(*new Crypto());
     }
 
+    NonnullRefPtr<SubtleCrypto> subtle() const { return m_subtle; }
+
     DOM::ExceptionOr<JS::Value> get_random_values(JS::Value array) const;
 
 private:
-    Crypto() = default;
+    Crypto();
+
+    NonnullRefPtr<SubtleCrypto> m_subtle;
 };
 
 }

Userland/Libraries/LibWeb/Crypto/Crypto.idl

@@ -1,6 +1,6 @@
 [Exposed=(Window,Worker)]
 interface Crypto {
-  // TODO: [SecureContext] readonly attribute SubtleCrypto subtle;
+  [SecureContext] readonly attribute SubtleCrypto subtle;
 
   // FIXME: the argument and the return value should be of type ArrayBufferView
   any getRandomValues(any array);

Userland/Libraries/LibWeb/Crypto/SubtleCrypto.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/Bindings/Wrappable.h>
+
+namespace Web::Crypto {
+
+class SubtleCrypto
+    : public Bindings::Wrappable
+    , public RefCounted<SubtleCrypto> {
+public:
+    using WrapperType = Bindings::SubtleCryptoWrapper;
+
+    static NonnullRefPtr<SubtleCrypto> create()
+    {
+        return adopt_ref(*new SubtleCrypto());
+    }
+
+private:
+    SubtleCrypto() = default;
+};
+
+}
+
+namespace Web::Bindings {
+
+SubtleCryptoWrapper* wrap(JS::GlobalObject&, Crypto::SubtleCrypto&);
+
+}

Userland/Libraries/LibWeb/Crypto/SubtleCrypto.idl

@@ -0,0 +1,3 @@
+[SecureContext,Exposed=(Window,Worker)]
+interface SubtleCrypto {
+};