Refactor ResourceHandler API.

content/browser/loader/null_resource_controller.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 "content/browser/loader/null_resource_controller.h"
+
+#include "base/logging.h"
+
+namespace content {
+
+NullResourceController::NullResourceController(bool* was_resumed)
+    : was_resumed_(was_resumed) {
+  *was_resumed = false;
+}
+
+NullResourceController::~NullResourceController() {}
+
+void NullResourceController::Cancel() {
+  DCHECK(!*was_resumed_);
+}
+
+void NullResourceController::CancelAndIgnore() {
+  DCHECK(!*was_resumed_);
+}
+
+void NullResourceController::CancelWithError(int error_code) {
+  DCHECK(!*was_resumed_);
+}
+
+void NullResourceController::Resume() {
+  *was_resumed_ = true;
+}
+
+}  // namespace content