[sync] Invoke new APIs in TrustedVaultClientBackend

This includes:
1. ClearLocalData, as per pre-existing TODO.
2. GetPublicKeyForIdentity, as part of registration verification.
3. SetDeviceRegistrationPublicKeyVerifierForUMA, guarded behind
   experiment toggle, to actually trigger registration verification.

The internal implementation of the APIs being invoked in this patch
landed recently with https://crrev.com/i/5496191.

The actual logic to verify the registration will be tackled in future
patches as it is quite complex.

Bug: 1416626, 1273080
Change-Id: I0c16aed7de2be3c63d1c213000e3f01b7da499ca
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4275301
Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Commit-Queue: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1108830}

ios/chrome/browser/providers/signin/chromium_trusted_vault.mm

@@ -98,7 +98,7 @@ void GetPublicKeyForIdentity(id<SystemIdentity> identity,
 void ChromiumTrustedVaultClientBackend::ClearLocalData(
     id<SystemIdentity> identity,
     base::OnceCallback<void(bool)> callback) {
-  NOTREACHED();
+  // Do nothing.
 }
 
 void ChromiumTrustedVaultClientBackend::GetPublicKeyForIdentity(

ios/chrome/browser/signin/trusted_vault_client_backend.h

@@ -52,9 +52,8 @@ class TrustedVaultClientBackend : public KeyedService {
 
   // Registers a delegate-like callback that implements device registration
   // verification.
-  // TODO(crbug.com/1416626): Make abstract once all implementations land.
   virtual void SetDeviceRegistrationPublicKeyVerifierForUMA(
-      VerifierCallback verifier);
+      VerifierCallback verifier) = 0;
 
   // Asynchronously fetches the shared keys for `identity` and invokes
   // `callback` with the fetched keys.
@@ -102,14 +101,12 @@ class TrustedVaultClientBackend : public KeyedService {
 
   // Clears local data belonging to `identity`, such as shared keys. This
   // excludes the physical client's key pair, which remains unchanged.
-  // TODO(crbug.com/1416626): Make abstract once all implementations land.
   virtual void ClearLocalData(id<SystemIdentity> identity,
-                              base::OnceCallback<void(bool)> callback);
+                              base::OnceCallback<void(bool)> callback) = 0;
 
   // Returns the member public key used to enroll the local device.
-  // TODO(crbug.com/1416626): Make abstract once all implementations land.
   virtual void GetPublicKeyForIdentity(id<SystemIdentity> identity,
-                                       GetPublicKeyCallback callback);
+                                       GetPublicKeyCallback callback) = 0;
 };
 
 #endif  // IOS_CHROME_BROWSER_SIGNIN_TRUSTED_VAULT_CLIENT_BACKEND_H_

ios/chrome/browser/signin/trusted_vault_client_backend.mm

@@ -4,30 +4,10 @@
 
 #import "ios/chrome/browser/signin/trusted_vault_client_backend.h"
 
-#import "base/functional/callback.h"
-#import "base/notreached.h"
-
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 TrustedVaultClientBackend::TrustedVaultClientBackend() = default;
 
 TrustedVaultClientBackend::~TrustedVaultClientBackend() = default;
-
-void TrustedVaultClientBackend::SetDeviceRegistrationPublicKeyVerifierForUMA(
-    VerifierCallback verifier) {
-  NOTREACHED();
-}
-
-void TrustedVaultClientBackend::ClearLocalData(
-    id<SystemIdentity> identity,
-    base::OnceCallback<void(bool)> callback) {
-  NOTREACHED();
-}
-
-void TrustedVaultClientBackend::GetPublicKeyForIdentity(
-    id<SystemIdentity> identity,
-    GetPublicKeyCallback callback) {
-  NOTREACHED();
-}

ios/chrome/browser/sync/ios_trusted_vault_client.h

@@ -5,6 +5,7 @@
 #ifndef IOS_CHROME_BROWSER_SYNC_IOS_TRUSTED_VAULT_CLIENT_H_
 #define IOS_CHROME_BROWSER_SYNC_IOS_TRUSTED_VAULT_CLIENT_H_
 
+#include "base/memory/weak_ptr.h"
 #include "components/sync/driver/trusted_vault_client.h"
 
 class ChromeAccountManagerService;
@@ -47,9 +48,14 @@ class IOSTrustedVaultClient : public syncer::TrustedVaultClient {
  private:
   // Returns the identity for `account_info`.
   id<SystemIdentity> IdentityForAccount(const CoreAccountInfo& account_info);
+  void VerifyDeviceRegistration(const std::string& gaia_id);
+  void VerifyDeviceRegistrationWithPublicKey(
+      const std::string& gaia_id,
+      const std::vector<uint8_t>& public_key);
 
   ChromeAccountManagerService* const account_manager_service_ = nullptr;
   TrustedVaultClientBackend* const backend_ = nullptr;
+  base::WeakPtrFactory<IOSTrustedVaultClient> weak_ptr_factory_{this};
 };
 
 #endif  // IOS_CHROME_BROWSER_SYNC_IOS_TRUSTED_VAULT_CLIENT_H_

ios/chrome/browser/sync/ios_trusted_vault_client.mm

@@ -4,7 +4,10 @@
 
 #import "ios/chrome/browser/sync/ios_trusted_vault_client.h"
 
+#import "base/feature_list.h"
+#import "base/functional/callback_helpers.h"
 #import "components/signin/public/identity_manager/account_info.h"
+#import "components/sync/base/features.h"
 #import "ios/chrome/browser/signin/chrome_account_manager_service.h"
 #import "ios/chrome/browser/signin/trusted_vault_client_backend.h"
 
@@ -19,6 +22,13 @@
       backend_(trusted_vault_client_backend) {
   DCHECK(account_manager_service_);
   DCHECK(backend_);
+
+  if (base::FeatureList::IsEnabled(
+          syncer::kSyncTrustedVaultVerifyDeviceRegistration)) {
+    backend_->SetDeviceRegistrationPublicKeyVerifierForUMA(
+        base::BindOnce(&IOSTrustedVaultClient::VerifyDeviceRegistration,
+                       weak_ptr_factory_.GetWeakPtr()));
+  }
 }
 
 IOSTrustedVaultClient::~IOSTrustedVaultClient() = default;
@@ -74,11 +84,27 @@
 
 void IOSTrustedVaultClient::ClearDataForAccount(
     const CoreAccountInfo& account_info) {
-  // TODO(crbug.com/1273080): decide whether this logic needs to be implemented
-  // on iOS.
+  backend_->ClearLocalData(IdentityForAccount(account_info), base::DoNothing());
 }
 
 id<SystemIdentity> IOSTrustedVaultClient::IdentityForAccount(
     const CoreAccountInfo& account_info) {
   return account_manager_service_->GetIdentityWithGaiaID(account_info.gaia);
 }
+
+void IOSTrustedVaultClient::VerifyDeviceRegistration(
+    const std::string& gaia_id) {
+  backend_->GetPublicKeyForIdentity(
+      account_manager_service_->GetIdentityWithGaiaID(gaia_id),
+      base::BindOnce(
+          &IOSTrustedVaultClient::VerifyDeviceRegistrationWithPublicKey,
+          weak_ptr_factory_.GetWeakPtr(), gaia_id));
+}
+
+void IOSTrustedVaultClient::VerifyDeviceRegistrationWithPublicKey(
+    const std::string& gaia_id,
+    const std::vector<uint8_t>& public_key) {
+  // TODO(crbug.com/1416626): Issue a request to the server and log the result
+  // to metrics.
+  NOTIMPLEMENTED();
+}