Add methods for creating V8 extras-based ReadableStreams from C++

Source/core/testing/ReadableStreamTestRequest.cpp

+// 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 "core/testing/ReadableStreamTestRequest.h"
+
+#include "bindings/core/v8/ToV8.h"
+#include "bindings/core/v8/V8Binding.h"
+#include "bindings/core/v8/V8HiddenValue.h"
+#include "core/streams/ReadableStream2.h"
+#include <v8.h>
+
+namespace blink {
+
+ReadableStreamTestRequest::ReadableStreamTestRequest(ScriptState* scriptState, UnderlyingSourceBase* underlyingSource)
+{
+    ScriptState::Scope scope(scriptState);
+
+    v8::Local<v8::Context> context = scriptState->context();
+    v8::Local<v8::Object> global = context->Global();
+    v8::Isolate* isolate = scriptState->isolate();
+    v8::Local<v8::Object> jsRequest = toV8(this, global, isolate).As<v8::Object>();
+
+    ScriptValue strategy = JSStreams::createCountQueuingStrategy(scriptState, 10);
+    ScriptValue stream = JSStreams::createReadableStream(scriptState, underlyingSource, strategy);
+
+    V8HiddenValue::setHiddenValue(isolate, jsRequest, V8HiddenValue::bodyStream(isolate), stream.v8Value());
+}
+
+ScriptValue ReadableStreamTestRequest::body(ScriptState* scriptState)
+{
+    ScriptState::Scope scope(scriptState);
+    v8::Isolate* isolate = scriptState->isolate();
+    v8::Local<v8::Object> global = scriptState->context()->Global();
+    v8::Local<v8::Object> jsRequest = toV8(this, global, isolate).As<v8::Object>();
+
+    v8::Local<v8::Value> result = V8HiddenValue::getHiddenValue(isolate, jsRequest, V8HiddenValue::bodyStream(isolate));
+
+    return ScriptValue(scriptState, result);
+}
+
+}