README

The internal implementation of //components/signin/public/identity_manager; visible only to implementation files in //components/signin/public/identity_manager. This directory contains implementations of pure interfaces in //components/signin/public/identity_manager as well as internal classes.

Here is how the various core internal classes support the public functionality of IdentityManager (see //components/signin/public/identity_manager/README.md for definitions of core terms):

• PrimaryAccountManager: Maintains the information of the primary account. When it is set/cleared, calls out to IdentityManager via callbacks, resulting in the firing of IdentityManager::Observer notifications. Setting/clearing occurs via PrimaryAccountMutatorImpl. Historically was exposed as SigninManager(Base).
• PrimaryAccountPolicyManager: Helper class for PrimaryAccountManager that manages interactions between policy and the primary account, e.g. clearing the primary account if signin becomes disallowed by policy. Historically was contained within SigninManager.
• ProfileOAuth2TokenService: Manages the OAuth2 tokens for the user's Gaia accounts. Delegates much of the functionality for refresh tokens to its various platform-specific delegates, and delegates much of the functionality for access tokens to the lower-level OAuth2AccessTokenManager class. Supports the IdentityManager APIs for querying the state of the accounts with refresh tokens and for fetching access tokens via (PrimaryAccount)AccessTokenFetcher. Mutation of refresh tokens occurs via platform-specific flows:
  • AcccountsMutatorImpl on desktop
  • DeviceAccountsSynchronizerImpl on iOS
  • Within the token service delegate by observing AccountManager on ChromeOS
  • Via a legacy flow on Android (https://crbug.com/963391) Has an observer API (ProfileOAuth2TokenServiceObserver); IdentityManager observes token-related events via this API in order to fire IdentityManager::Observer events. Other internal classes also observe token-related events, which is why PO2TS still has observers rather than directly calling out to IdentityManager via callbacks as other internal classes do.
• ProfileOAuth2TokenServiceDelegate: Mostly-abstract class via which ProfileOAuth2TokenService interacts with platform-specific functionality for OAuth2 tokens. Has various platform-specific implementations. The platform-specific implementations glue the cross-platform ProfileOAuth2TokenService interface to the underlying platform support, and dictate the firing of ProfileOAuth2TokenServiceObserver events.
• AccountTrackerService: Maintains the mapping from account ID to account information for the user's Gaia accounts with refresh tokens. Supports the various IdentityManager::FindAccountInfoXXX() methods. When account info is updated/removed for a given account, calls out to IdentityManager via callbacks, resulting in the firing of IdentityManager::Observer notifications. Conceptually below ProfileOAuth2TokenService, as it is needed by various platform-specific implementations of ProfileOAuth2TokenServiceDelegate, which themselves are needed by ProfileOAuth2TokenService.
• AccountFetcherService: Fetches account information for the user's Gaia accounts with refresh tokens in order to populate this information in AccountTrackerService. Observes ProfileOAuth2TokenService in order to observe addition and removal of accounts with refresh tokens to initiate fetching/removal of account information. Split from AccountTrackerService in order to support knowledge of ProfileOAuth2TokenService.
• GaiaCookieManagerService: Maintains information about the accounts in the Gaia cookie. Supports IdentityManager::GetAccountsInCookieJar(). When the accounts in the cookie are updated or the cookie itself is deleted, calls out to IdentityManager via callbacks, resulting in the firing of IdentityManager::Observer notifications.

The layering of the core internal classes is as follows, with higher-level classes listed first:

• PrimaryAccountManager
• AccountFetcherService
• GaiaCookieManagerService (note: GCMS and AFS are independent peers)
• ProfileOAuth2TokenService
• various ProfileOAuth2TokenServiceDelegate implementations
• AccountTrackerService