[iOS] Upstream web_controller_provider_impl.{h,mm}.

ios/public/provider/web/web_controller_provider_factory.mm

+// 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.
+
+#import "ios/public/provider/web/web_controller_provider_factory.h"
+
+#include "base/memory/ptr_util.h"
+#import "ios/public/provider/web/web_controller_provider.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace ios {
+namespace {
+WebControllerProviderFactory* g_web_controller_provider_factory;
+}
+
+WebControllerProviderFactory::WebControllerProviderFactory() {}
+
+WebControllerProviderFactory::~WebControllerProviderFactory() {}
+
+std::unique_ptr<WebControllerProvider>
+WebControllerProviderFactory::CreateWebControllerProvider(
+    web::BrowserState* browser_state) {
+  return base::MakeUnique<WebControllerProvider>(browser_state);
+}
+
+void SetWebControllerProviderFactory(
+    WebControllerProviderFactory* provider_factory) {
+  g_web_controller_provider_factory = provider_factory;
+}
+
+WebControllerProviderFactory* GetWebControllerProviderFactory() {
+  return g_web_controller_provider_factory;
+}
+
+}  // namespace ios