Use mojo for Chrome Loading, Part 1

content/browser/loader/url_loader_factory_holder.cc

+// Copyright 2016 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/url_loader_factory_holder.h"
+
+#include <memory>
+
+#include "base/bind.h"
+#include "base/memory/ptr_util.h"
+#include "content/browser/loader/resource_dispatcher_host_impl.h"
+#include "content/browser/loader/resource_message_filter.h"
+#include "content/common/resource_request.h"
+#include "content/common/url_loader.mojom.h"
+#include "content/common/url_loader_factory.mojom.h"
+#include "content/public/browser/browser_thread.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace content {
+
+// This class is an implementation of mojom::URLLoaderFactory that creates
+// a mojom::URLLoader.
+class URLLoaderFactoryHolder::URLLoaderFactoryImpl final
+    : public mojom::URLLoaderFactory {
+ public:
+  explicit URLLoaderFactoryImpl(
+      scoped_refptr<ResourceMessageFilter> resource_message_filter)
+      : resource_message_filter_(std::move(resource_message_filter)) {
+    DCHECK(resource_message_filter_);
+    DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  }
+  ~URLLoaderFactoryImpl() override { DCHECK_CURRENTLY_ON(BrowserThread::IO); }
+
+  void CreateLoaderAndStart(mojom::URLLoaderRequest request,
+                            int32_t request_id,
+                            const ResourceRequest& url_request,
+                            mojom::URLLoaderClientPtr client) override {
+    DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+    // TODO(yhirano): Provide the right routing ID.
+    const int routing_id = 0;
+    ResourceDispatcherHostImpl* rdh = ResourceDispatcherHostImpl::Get();
+    rdh->OnRequestResourceWithMojo(routing_id, request_id, url_request,
+                                   std::move(request), std::move(client),
+                                   resource_message_filter_.get());
+  }
+
+  void Bind(mojo::InterfaceRequest<mojom::URLLoaderFactory> request) {
+    DCHECK_CURRENTLY_ON(BrowserThread::IO);
+    binding_.reset(
+        new mojo::Binding<URLLoaderFactory>(this, std::move(request)));
+  }
+
+ private:
+  scoped_refptr<ResourceMessageFilter> resource_message_filter_;
+  std::unique_ptr<mojo::Binding<mojom::URLLoaderFactory>> binding_;
+
+  DISALLOW_COPY_AND_ASSIGN(URLLoaderFactoryImpl);
+};
+
+URLLoaderFactoryHolder::URLLoaderFactoryHolder(
+    scoped_refptr<ResourceMessageFilter> resource_message_filter,
+    mojo::InterfaceRequest<mojom::URLLoaderFactory> request)
+    : factory_(new URLLoaderFactoryImpl(resource_message_filter)) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  // This |Unretained| is safe because ~URLLoaderFactoryHolder is the only
+  // function that posts a |factory_| deletion task to the IO thread and
+  // ~URLLoaderFactoryHolder is called on this thread.
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&URLLoaderFactoryImpl::Bind, base::Unretained(factory_.get()),
+                 base::Passed(std::move(request))));
+}
+
+URLLoaderFactoryHolder::~URLLoaderFactoryHolder() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  BrowserThread::DeleteSoon(BrowserThread::IO, FROM_HERE, factory_.release());
+}
+
+}  // namespace content