[iOS] Upstream UpdatableConfig test provider

ios/public/test/test_updatable_resource_provider.h

+// Copyright 2015 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 IOS_PUBLIC_TEST_TEST_UPDATABLE_RESOURCE_PROVIDER_H_
+#define IOS_PUBLIC_TEST_TEST_UPDATABLE_RESOURCE_PROVIDER_H_
+
+#import "ios/public/provider/chrome/browser/updatable_resource_provider.h"
+
+namespace ios {
+
+// Dummy UpdatableResourceProvider implementation that simply loads data from
+// the specified plist file.
+class TestUpdatableResourceProvider : public ios::UpdatableResourceProvider {
+ private:
+  // UpdatableResourceProvider implementation.
+  NSString* GetUpdateNotificationName() override;
+  id<UpdatableResourceBridge> CreateUpdatableResource(
+      NSString* resource_identifier,
+      id<UpdatableResourceDelegate> delegate) override;
+};
+
+}  // namespace ios
+
+#endif  // IOS_PUBLIC_TEST_TEST_UPDATABLE_RESOURCE_PROVIDER_H_