Convert GetSearchProviderInstallState to Mojo

content/public/browser/owned_interface.h

+// Copyright (c) 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.
+
+#ifndef CONTENT_BROWSER_OWNED_INTERFACE_H_
+#define CONTENT_BROWSER_OWNED_INTERFACE_H_
+
+#include <memory>
+
+#include "base/memory/ptr_util.h"
+#include "base/memory/ref_counted.h"
+
+namespace content {
+
+// Common base class for interface impls, allowing them to be stored in a
+// type-erased container for ownership management.
+class OwnedInterface {
+ public:
+  OwnedInterface() = default;
+  virtual ~OwnedInterface() = default;
+};
+
+template <typename InterfaceImpl>
+class DeleteOnTaskRunner {
+ public:
+  DeleteOnTaskRunner(
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner = nullptr)
+      : task_runner_(task_runner) {}
+  void operator()(const InterfaceImpl* impl) {
+    if (task_runner_) {
+      if (!task_runner_->DeleteSoon(FROM_HERE, impl)) {
+#if defined(UNIT_TEST)
+        // Only logged under unit testing because leaks at shutdown
+        // are acceptable under normal circumstances.
+        LOG(ERROR) << "DeleteSoon failed on thread";
+#endif  // UNIT_TEST
+      }
+    } else {
+      delete impl;
+    }
+  }
+  ~DeleteOnTaskRunner() = default;
+
+ private:
+  const scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+};
+
+template <typename InterfaceImpl>
+class OwnedInterfaceImpl : public OwnedInterface {
+ public:
+  OwnedInterfaceImpl(
+      std::unique_ptr<InterfaceImpl> impl,
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner = nullptr)
+      : impl_(impl.release(), DeleteOnTaskRunner<InterfaceImpl>(task_runner)) {}
+
+  ~OwnedInterfaceImpl() = default;
+
+  // The returned pointer is owned by this object, which must outlive it.
+  InterfaceImpl* get() { return impl_.get(); }
+
+ private:
+  std::unique_ptr<InterfaceImpl, DeleteOnTaskRunner<InterfaceImpl>> impl_;
+
+  DISALLOW_COPY_AND_ASSIGN(OwnedInterfaceImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_OWNED_INTERFACE_H_