Refactor ResourceHandler API.

content/browser/loader/resource_handler.cc

 // Copyright (c) 2012 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/resource_handler.h"
 
 #include "content/browser/loader/resource_request_info_impl.h"
 
 namespace content {
 
+ResourceHandler::Delegate::Delegate() {}
+
+ResourceHandler::Delegate::~Delegate() {}
+
+void ResourceHandler::SetDelegate(Delegate* delegate) {
+  delegate_ = delegate;
+}
+
 ResourceHandler::~ResourceHandler() {}
 
 ResourceHandler::ResourceHandler(net::URLRequest* request)
-    : controller_(NULL),
-      request_(request) {
+    : request_(request) {}
+
+void ResourceHandler::HoldController(
+    std::unique_ptr<ResourceController> controller) {
+  controller_ = std::move(controller);
 }
 
-void ResourceHandler::SetController(ResourceController* controller) {
-  controller_ = controller;
+std::unique_ptr<ResourceController> ResourceHandler::ReleaseController() {
+  DCHECK(controller_);
+
+  // Can't use std::move, as that doesn't allow subsequently checking if
+  // |controller_| is null or not.

[Charlie Harrison, 2017/01/25 20:23:00]

Are you sure? I thought move semantics guaranteed that comparison with nullptr
would work after moving.

[mmenke, 2017/01/25 22:07:59]

You're right...It's not guaranteed be std::move in general, but it is guaranteed
for std::move(unique_ptr).

+  std::unique_ptr<ResourceController> controller;
+  std::swap(controller, controller_);
+  return controller;
+}
+
+void ResourceHandler::Resume() {
+  ReleaseController()->Resume();
+}
+
+void ResourceHandler::Cancel() {
+  ReleaseController()->Cancel();
+}
+
+void ResourceHandler::CancelAndIgnore() {
+  ReleaseController()->CancelAndIgnore();
+}
+
+void ResourceHandler::CancelWithError(int error_code) {
+  ReleaseController()->CancelWithError(error_code);
+}
+
+void ResourceHandler::OutOfBandCancel(int error_code, bool tell_renderer) {
+  delegate_->OutOfBandCancel(error_code, tell_renderer);
 }
 
 ResourceRequestInfoImpl* ResourceHandler::GetRequestInfo() const {
   return ResourceRequestInfoImpl::ForRequest(request_);
 }
 
 int ResourceHandler::GetRequestID() const {
   return GetRequestInfo()->GetRequestID();
 }
 
 ResourceMessageFilter* ResourceHandler::GetFilter() const {
   return GetRequestInfo()->requester_info()->filter();
 }
 
 }  // namespace content