[iOS] Adding abstract class for ChromeTrustedVaultService.

ChromeTrustedVaultService is an abstract class to support the trusted
vault on iOS. Also this patch adds
ChromeBrowserProvider::GetChromeTrustedValueService().
This method needs to be overridden by ChromeBrowserProviderImpl

Related:
=> crrev.com/c/2111302 ChromeTrustedVaultService
 - crrev.com/i/2774364 ChromeTrustedVaultServiceImpl
 - crrev.com/c/2118054 IOSTrustedVaultClient

Bug: 1019685
Change-Id: Ia6a4384a9e74655427f435f09a9871d104953309
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2116079
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754032}

ios/public/provider/chrome/browser/chrome_browser_provider.h

@@ -47,6 +47,7 @@ namespace ios {
 
 class ChromeBrowserProvider;
 class ChromeIdentityService;
+class ChromeTrustedVaultService;
 class GeolocationUpdaterProvider;
 class SigninErrorProvider;
 class SigninResourcesProvider;
@@ -104,6 +105,8 @@ class ChromeBrowserProvider {
       std::unique_ptr<ChromeIdentityService> service);
   // Returns an instance of a Chrome identity service.
   virtual ChromeIdentityService* GetChromeIdentityService();
+  // Returns an instance of a Chrome trusted vault service.
+  virtual ChromeTrustedVaultService* GetChromeTrustedVaultService();
   // Returns an instance of a GeolocationUpdaterProvider.
   virtual GeolocationUpdaterProvider* GetGeolocationUpdaterProvider();
   // Returns risk data used in Wallet requests.

ios/public/provider/chrome/browser/chrome_browser_provider.mm

@@ -59,6 +59,11 @@ ChromeIdentityService* ChromeBrowserProvider::GetChromeIdentityService() {
   return nullptr;
 }
 
+ChromeTrustedVaultService*
+ChromeBrowserProvider::GetChromeTrustedVaultService() {
+  return nullptr;
+}
+
 GeolocationUpdaterProvider*
 ChromeBrowserProvider::GetGeolocationUpdaterProvider() {
   return nullptr;

ios/public/provider/chrome/browser/signin/BUILD.gn

@@ -12,6 +12,8 @@ source_set("signin") {
     "chrome_identity_interaction_manager.mm",
     "chrome_identity_service.h",
     "chrome_identity_service.mm",
+    "chrome_trusted_vault_service.h",
+    "chrome_trusted_vault_service.mm",
     "signin_error_provider.h",
     "signin_error_provider.mm",
     "signin_resources_provider.h",

ios/public/provider/chrome/browser/signin/chrome_trusted_vault_service.h

+// Copyright 2020 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_PROVIDER_CHROME_BROWSER_SIGNIN_CHROME_TRUSTED_VAULT_SERVICE_H_
+#define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_SIGNIN_CHROME_TRUSTED_VAULT_SERVICE_H_
+
+#include <vector>
+
+#include "base/callback.h"
+#include "base/macros.h"
+
+@class ChromeIdentity;
+
+namespace ios {
+
+using TrustedVaultSharedKey = std::vector<uint8_t>;
+using TrustedVaultSharedKeyList = std::vector<TrustedVaultSharedKey>;
+
+// Abstract class to manage shared keys.
+class ChromeTrustedVaultService {
+ public:
+  ChromeTrustedVaultService();
+  virtual ~ChromeTrustedVaultService();
+
+  // Asynchronously fetch the shared keys for |identity|
+  // and returns them by calling |callback|.
+  virtual void FetchKeys(
+      ChromeIdentity* chrome_identity,
+      base::OnceCallback<void(const TrustedVaultSharedKeyList&)> callback);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ChromeTrustedVaultService);
+};
+
+}  // namespace ios
+
+#endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_SIGNIN_CHROME_TRUSTED_VAULT_SERVICE_H_

ios/public/provider/chrome/browser/signin/chrome_trusted_vault_service.mm

+// Copyright 2020 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/signin/chrome_trusted_vault_service.h"
+
+#import "base/logging.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+namespace ios {
+
+ChromeTrustedVaultService::ChromeTrustedVaultService() {}
+
+ChromeTrustedVaultService::~ChromeTrustedVaultService() {}
+
+void ChromeTrustedVaultService::FetchKeys(
+    ChromeIdentity* chrome_identity,
+    base::OnceCallback<void(const TrustedVaultSharedKeyList&)> callback) {
+  NOTREACHED();
+}
+
+}  // namespace ios