[Gin] Add Arguments::GetHolderCreationContext()

gin/arguments_unittest.cc

+// Copyright 2017 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 "gin/arguments.h"
+
+#include "base/bind.h"
+#include "gin/converter.h"
+#include "gin/object_template_builder.h"
+#include "gin/public/isolate_holder.h"
+#include "gin/test/v8_test.h"
+#include "v8/include/v8.h"
+
+namespace gin {
+
+using ArgumentsTest = V8Test;
+
+// Test that Arguments::GetHolderCreationContext returns the proper context.
+TEST_F(ArgumentsTest, TestArgumentsHolderCreationContext) {
+  v8::Isolate* isolate = instance_->isolate();
+  v8::HandleScope handle_scope(isolate);
+
+  v8::Local<v8::Context> creation_context = context_.Get(instance_->isolate());
+
+  auto check_creation_context = [](v8::Local<v8::Context> expected_context,
+                                   gin::Arguments* arguments) {
+    EXPECT_EQ(expected_context, arguments->GetHolderCreationContext());
+  };
+
+  // Create an object that will compare GetHolderCreationContext() with
+  // |creation_context|.
+  v8::Local<v8::ObjectTemplate> object_template =
+      ObjectTemplateBuilder(isolate)
+          .SetMethod("checkCreationContext",
+                     base::Bind(check_creation_context, creation_context))
+          .Build();
+
+  v8::Local<v8::Object> object =
+      object_template->NewInstance(creation_context).ToLocalChecked();
+
+  // Call checkCreationContext() on the generated object using the passed-in
+  // context as the current context.
+  auto test_context = [object, isolate](v8::Local<v8::Context> context) {
+    v8::Context::Scope context_scope(context);
+    const char kCallFunction[] = "(function(o) { o.checkCreationContext(); })";
+    v8::Local<v8::Script> script =
+        v8::Script::Compile(context, StringToV8(isolate, kCallFunction))
+            .ToLocalChecked();
+    v8::Local<v8::Function> function;
+    ASSERT_TRUE(ConvertFromV8(isolate, script->Run(), &function));
+    v8::Local<v8::Value> args[] = {object};
+    function->Call(v8::Undefined(isolate), arraysize(args), args);
+  };
+
+  // Test calling in the creation context.
+  test_context(creation_context);
+
+  {
+    // Create a second context, and test calling in that. The creation context
+    // should be the same (even though the current context has changed).
+    v8::Local<v8::Context> second_context =
+        v8::Context::New(isolate, nullptr, v8::Local<v8::ObjectTemplate>());
+    test_context(second_context);
+  }
+}
+
+}  // namespace gin