[ios] Adds BrandedImageProvider and its associated image resources.

ios/public/provider/chrome/browser/images/branded_image_provider.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/chrome/browser/images/branded_image_provider.h"
+
+#import <Foundation/Foundation.h>
+
+BrandedImageProvider::BrandedImageProvider() {}
+
+BrandedImageProvider::~BrandedImageProvider() {}
+
+UIImage* BrandedImageProvider::GetAccountsListActivityControlsImage() {
+  return nil;
+}
+
+UIImage* BrandedImageProvider::GetClearBrowsingDataAccountActivityImage() {
+  return nil;
+}
+
+UIImage* BrandedImageProvider::GetClearBrowsingDataSiteDataImage() {
+  return nil;
+}
+
+UIImage* BrandedImageProvider::GetContextualSearchHeaderImage() {
+  return nil;
+}
+
+UIImage* BrandedImageProvider::GetSigninConfirmationSyncSettingsImage() {
+  return nil;
+}
+
+UIImage* BrandedImageProvider::GetSigninConfirmationPersonalizeServicesImage() {
+  return nil;
+}
+
+bool BrandedImageProvider::GetToolbarVoiceSearchButtonImageId(int* image_id) {
+  return false;
+}
+
+UIImage* BrandedImageProvider::GetWhatsNewIconImage(WhatsNewIcon type) {
+  return nil;
+}