Simplify token retrieval logic in TokenHandleFetcher

Instead of relying on an implementation of IdentityManager::Observer and
a private flag to know when a RefreshToken is available before requesting
using PrimaryAccountAccessTokenFetcher, use PAATF's mode to wait until the
primary account has a refresh token available (i.e. kWaitUntilAvailable)
whenever needed when TokenHandleFetcher::BackfillToken() is invoked, or
simply using kImmediate if such refresh token is already available.

Bug: 905689
Change-Id: Idf8e8b58a9bda518f2bd11d140b4e8776194a8f4
Reviewed-on: https://chromium-review.googlesource.com/c/1343264
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611079}

chrome/browser/chromeos/login/signin/token_handle_fetcher.cc

@@ -12,6 +12,7 @@
 #include "chrome/browser/signin/identity_manager_factory.h"
 #include "components/keyed_service/content/browser_context_keyed_service_shutdown_notifier_factory.h"
 #include "google_apis/gaia/gaia_constants.h"
+#include "services/identity/public/cpp/identity_manager.h"
 #include "services/identity/public/cpp/primary_account_access_token_fetcher.h"
 #include "services/identity/public/cpp/scope_set.h"
 #include "services/network/public/cpp/shared_url_loader_factory.h"
@@ -47,10 +48,7 @@ TokenHandleFetcher::TokenHandleFetcher(TokenHandleUtil* util,
                                        const AccountId& account_id)
     : token_handle_util_(util), account_id_(account_id) {}
 
-TokenHandleFetcher::~TokenHandleFetcher() {
-  if (waiting_for_refresh_token_)
-    identity_manager_->RemoveObserver(this);
-}
+TokenHandleFetcher::~TokenHandleFetcher() {}
 
 void TokenHandleFetcher::BackfillToken(Profile* profile,
                                        const TokenFetchingCallback& callback) {
@@ -58,33 +56,17 @@ void TokenHandleFetcher::BackfillToken(Profile* profile,
   callback_ = callback;
 
   identity_manager_ = IdentityManagerFactory::GetForProfile(profile);
-  const std::string user_email = identity_manager_->GetPrimaryAccountId();
-  if (!identity_manager_->HasAccountWithRefreshToken(user_email)) {
-    account_without_token_ = user_email;
+  if (!identity_manager_->HasPrimaryAccountWithRefreshToken()) {
     profile_shutdown_notification_ =
         TokenHandleFetcherShutdownNotifierFactory::GetInstance()
             ->Get(profile)
             ->Subscribe(base::Bind(&TokenHandleFetcher::OnProfileDestroyed,
                                    base::Unretained(this)));
-
-    identity_manager_->AddObserver(this);
-    waiting_for_refresh_token_ = true;
-    return;
   }
-  RequestAccessToken(user_email);
-}
-
-void TokenHandleFetcher::OnRefreshTokenUpdatedForAccount(
-    const AccountInfo& account_info,
-    bool is_valid) {
-  if (account_without_token_ != account_info.email)
-    return;
-  waiting_for_refresh_token_ = false;
-  identity_manager_->RemoveObserver(this);
-  RequestAccessToken(account_info.email);
-}
 
-void TokenHandleFetcher::RequestAccessToken(const std::string& user_email) {
+  // Now we can request the token, knowing that it will be immediately requested
+  // if the refresh token is available, or that it will be requested once the
+  // refresh token is available for the primary account.
   identity::ScopeSet scopes;
   scopes.insert(GaiaConstants::kOAuth1LoginScope);
 
@@ -92,12 +74,12 @@ void TokenHandleFetcher::RequestAccessToken(const std::string& user_email) {
   // owned by this object (thus destroyed when this object is destroyed) and
   // PrimaryAccountAccessTokenFetcher guarantees that it doesn't invoke its
   // callback after it is destroyed.
-  access_token_fetcher_ =
-      std::make_unique<identity::PrimaryAccountAccessTokenFetcher>(
+  access_token_fetcher_ = std::make_unique<
+      identity::PrimaryAccountAccessTokenFetcher>(
       kAccessTokenFetchId, identity_manager_, scopes,
       base::BindOnce(&TokenHandleFetcher::OnAccessTokenFetchComplete,
                      base::Unretained(this)),
-          identity::PrimaryAccountAccessTokenFetcher::Mode::kImmediate);
+      identity::PrimaryAccountAccessTokenFetcher::Mode::kWaitUntilAvailable);
 }
 
 void TokenHandleFetcher::OnAccessTokenFetchComplete(

chrome/browser/chromeos/login/signin/token_handle_fetcher.h

@@ -14,10 +14,10 @@
 #include "components/account_id/account_id.h"
 #include "components/keyed_service/core/keyed_service_shutdown_notifier.h"
 #include "google_apis/gaia/gaia_oauth_client.h"
-#include "services/identity/public/cpp/identity_manager.h"
+#include "services/identity/public/cpp/primary_account_access_token_fetcher.h"
 
 namespace identity {
-class PrimaryAccountAccessTokenFetcher;
+class IdentityManager;
 }
 
 class TokenHandleUtil;
@@ -28,8 +28,7 @@ class Profile;
 // an OAuth2 token available. If there is profile already loaded, then
 // minting additional access token might be required.
 
-class TokenHandleFetcher : public gaia::GaiaOAuthClient::Delegate,
-                           public identity::IdentityManager::Observer {
+class TokenHandleFetcher : public gaia::GaiaOAuthClient::Delegate {
  public:
   TokenHandleFetcher(TokenHandleUtil* util, const AccountId& account_id);
   ~TokenHandleFetcher() override;
@@ -46,10 +45,6 @@ class TokenHandleFetcher : public gaia::GaiaOAuthClient::Delegate,
   void BackfillToken(Profile* profile, const TokenFetchingCallback& callback);
 
  private:
-  // identity::IdentityManager::Observer override:
-  void OnRefreshTokenUpdatedForAccount(const AccountInfo& account_info,
-                                       bool is_valid) override;
-
   // AccessTokenFetcher::TokenCallback for PrimaryAccountAccessTokenFetcher.
   void OnAccessTokenFetchComplete(GoogleServiceAuthError error,
                                   identity::AccessTokenInfo token_info);
@@ -60,7 +55,6 @@ class TokenHandleFetcher : public gaia::GaiaOAuthClient::Delegate,
   void OnGetTokenInfoResponse(
       std::unique_ptr<base::DictionaryValue> token_info) override;
 
-  void RequestAccessToken(const std::string& user_email);
   void FillForAccessToken(const std::string& access_token);
 
   // This is called before profile is detroyed.
@@ -70,8 +64,6 @@ class TokenHandleFetcher : public gaia::GaiaOAuthClient::Delegate,
   AccountId account_id_;
   identity::IdentityManager* identity_manager_ = nullptr;
 
-  bool waiting_for_refresh_token_ = false;
-  std::string account_without_token_;
   Profile* profile_ = nullptr;
   base::TimeTicks tokeninfo_response_start_time_ = base::TimeTicks();
   TokenFetchingCallback callback_;