Extract ArcSupportMessageHost.

chrome/browser/chromeos/arc/extensions/arc_support_message_host.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 "chrome/browser/chromeos/arc/extensions/arc_support_message_host.h"
+
+#include "base/json/json_reader.h"
+#include "base/json/json_writer.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "chrome/browser/chromeos/arc/arc_auth_service.h"
+#include "chrome/browser/chromeos/arc/arc_support_host.h"
+
+namespace arc {
+
+// static
+const char ArcSupportMessageHost::kHostName[] = "com.google.arc_support";
+
+// static
+const char* const ArcSupportMessageHost::kHostOrigin[] = {
+    "chrome-extension://cnbgggchhmkkdmeppjobngjoejnihlei/"};
+
+// static
+std::unique_ptr<extensions::NativeMessageHost> ArcSupportMessageHost::Create() {
+  return std::unique_ptr<NativeMessageHost>(new ArcSupportMessageHost());
+}
+
+ArcSupportMessageHost::ArcSupportMessageHost() = default;
+
+ArcSupportMessageHost::~ArcSupportMessageHost() {
+  // On shutdown, ArcAuthService may be already deleted. In that case,
+  // ArcAuthService::Get() returns nullptr. Note that, ArcSupportHost
+  // disconnects to this instance on shutdown already.
+  ArcAuthService* auth_service = ArcAuthService::Get();
+  if (auth_service) {
+    DCHECK(auth_service->support_host());
+    auth_service->support_host()->UnsetMessageHost(this);
+  }
+}
+
+void ArcSupportMessageHost::SendMessage(const base::Value& message) {
+  if (!client_)
+    return;
+
+  std::string message_string;
+  base::JSONWriter::Write(message, &message_string);
+  client_->PostMessageFromNativeHost(message_string);
+}
+
+void ArcSupportMessageHost::SetObserver(Observer* observer) {
+  // We assume that the observer instance is only ArcSupportHost, which is
+  // currently system unique. This is also used to reset the observere,
+  // so |observer| xor |observer_| needs to be nullptr.
+  DCHECK(!observer != !observer_);
+  observer_ = observer;
+}
+
+void ArcSupportMessageHost::Start(Client* client) {
+  DCHECK(!client_);
+  client_ = client;
+
+  ArcAuthService* auth_service = ArcAuthService::Get();
+  DCHECK(auth_service);
+  DCHECK(auth_service->support_host());
+  auth_service->support_host()->SetMessageHost(this);
+}
+
+void ArcSupportMessageHost::OnMessage(const std::string& message_string) {
+  if (!observer_)
+    return;
+
+  std::unique_ptr<base::Value> message_value =
+      base::JSONReader::Read(message_string);
+  base::DictionaryValue* message;
+  if (!message_value || !message_value->GetAsDictionary(&message)) {
+    NOTREACHED();
+    return;
+  }
+
+  observer_->OnMessage(*message);
+}
+
+scoped_refptr<base::SingleThreadTaskRunner> ArcSupportMessageHost::task_runner()
+    const {
+  return base::ThreadTaskRunnerHandle::Get();
+}
+
+}  // namespace arc