Add create access token fetcher to OAuthTokenService.

This CL add a factory method to create access token fetchers in the
OAuth2 token service. This allows subclasses to create specific access
token fetchers and re-use the OAuth2 caching logic without duplicating
the code.

TBR=atwilson,  blundell, gene
BUG=320625

Review URL: https://codereview.chromium.org/193043002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256816 0039d316-1c4b-4281-b951-d872f2087c98

11 files changed, 110 insertions, 89 deletions

diff --git a/google_apis/gaia/fake_oauth2_token_service.cc b/google_apis/gaia/fake_oauth2_token_service.cc
index b1d9054..f23f349 100644
--- a/google_apis/gaia/fake_oauth2_token_service.cc
+++ b/google_apis/gaia/fake_oauth2_token_service.cc
@@ -4,17 +4,11 @@
 
 #include "google_apis/gaia/fake_oauth2_token_service.h"
 
-FakeOAuth2TokenService::FakeOAuth2TokenService() {
-}
+FakeOAuth2TokenService::FakeOAuth2TokenService() : request_context_(NULL) {}
 
 FakeOAuth2TokenService::~FakeOAuth2TokenService() {
 }
 
-std::string FakeOAuth2TokenService::GetRefreshToken(
-    const std::string& account_id) const {
-  return std::string();
-}
-
 void FakeOAuth2TokenService::FetchOAuth2Token(
     RequestImpl* request,
     const std::string& account_id,
@@ -32,5 +26,24 @@ void FakeOAuth2TokenService::InvalidateOAuth2Token(
 }
 
 net::URLRequestContextGetter* FakeOAuth2TokenService::GetRequestContext() {
+  return request_context_;
+}
+
+bool FakeOAuth2TokenService::RefreshTokenIsAvailable(
+    const std::string& account_id) const {
+  return account_ids_.count(account_id) != 0;
+};
+
+void FakeOAuth2TokenService::AddAccount(const std::string& account_id) {
+  account_ids_.insert(account_id);
+}
+
+OAuth2AccessTokenFetcher* FakeOAuth2TokenService::CreateAccessTokenFetcher(
+    const std::string& account_id,
+    net::URLRequestContextGetter* getter,
+    OAuth2AccessTokenConsumer* consumer) {
+  // |FakeOAuth2TokenService| overrides |FetchOAuth2Token| and thus
+  // |CreateAccessTokenFetcher| should never be called.
+  NOTREACHED();
   return NULL;
 }
diff --git a/google_apis/gaia/fake_oauth2_token_service.h b/google_apis/gaia/fake_oauth2_token_service.h
index 2554bd4..8c267e5 100644
--- a/google_apis/gaia/fake_oauth2_token_service.h
+++ b/google_apis/gaia/fake_oauth2_token_service.h
@@ -5,6 +5,7 @@
 #ifndef GOOGLE_APIS_GAIA_FAKE_OAUTH2_TOKEN_SERVICE_H_
 #define GOOGLE_APIS_GAIA_FAKE_OAUTH2_TOKEN_SERVICE_H_
 
+#include <set>
 #include <string>
 
 #include "base/compiler_specific.h"
@@ -20,6 +21,12 @@ class FakeOAuth2TokenService : public OAuth2TokenService {
   FakeOAuth2TokenService();
   virtual ~FakeOAuth2TokenService();
 
+  void AddAccount(const std::string& account_id);
+
+  void set_request_context(net::URLRequestContextGetter* request_context) {
+    request_context_ = request_context;
+  }
+
  protected:
   // OAuth2TokenService overrides.
   virtual void FetchOAuth2Token(RequestImpl* request,
@@ -34,13 +41,21 @@ class FakeOAuth2TokenService : public OAuth2TokenService {
                                      const ScopeSet& scopes,
                                      const std::string& access_token) OVERRIDE;
 
-  virtual std::string GetRefreshToken(const std::string& account_id)
-      const OVERRIDE;
+  virtual bool RefreshTokenIsAvailable(const std::string& account_id) const
+      OVERRIDE;
 
  private:
   // OAuth2TokenService overrides.
   virtual net::URLRequestContextGetter* GetRequestContext() OVERRIDE;
 
+  virtual OAuth2AccessTokenFetcher* CreateAccessTokenFetcher(
+      const std::string& account_id,
+      net::URLRequestContextGetter* getter,
+      OAuth2AccessTokenConsumer* consumer) OVERRIDE;
+
+  std::set<std::string> account_ids_;
+  net::URLRequestContextGetter* request_context_;  // weak
+
   DISALLOW_COPY_AND_ASSIGN(FakeOAuth2TokenService);
 };
 
diff --git a/google_apis/gaia/oauth2_access_token_fetcher.h b/google_apis/gaia/oauth2_access_token_fetcher.h
index 241fe99..cd3ee5c 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher.h
+++ b/google_apis/gaia/oauth2_access_token_fetcher.h
@@ -36,7 +36,6 @@ class OAuth2AccessTokenFetcher {
   // a super-set of the specified scopes.
   virtual void Start(const std::string& client_id,
                      const std::string& client_secret,
-                     const std::string& refresh_token,
                      const std::vector<std::string>& scopes) = 0;
 
   // Cancels the current request and informs the consumer.
diff --git a/google_apis/gaia/oauth2_access_token_fetcher_impl.cc b/google_apis/gaia/oauth2_access_token_fetcher_impl.cc
index 67b4e6a..f4cd4f0 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher_impl.cc
+++ b/google_apis/gaia/oauth2_access_token_fetcher_impl.cc
@@ -130,8 +130,13 @@ scoped_ptr<base::DictionaryValue> ParseGetAccessTokenResponse(
 }  // namespace
 
 OAuth2AccessTokenFetcherImpl::OAuth2AccessTokenFetcherImpl(
-    OAuth2AccessTokenConsumer* consumer, URLRequestContextGetter* getter)
-    : OAuth2AccessTokenFetcher(consumer), getter_(getter), state_(INITIAL) {}
+    OAuth2AccessTokenConsumer* consumer,
+    net::URLRequestContextGetter* getter,
+    const std::string& refresh_token)
+    : OAuth2AccessTokenFetcher(consumer),
+      getter_(getter),
+      refresh_token_(refresh_token),
+      state_(INITIAL) {}
 
 OAuth2AccessTokenFetcherImpl::~OAuth2AccessTokenFetcherImpl() {}
 
@@ -140,11 +145,9 @@ void OAuth2AccessTokenFetcherImpl::CancelRequest() { fetcher_.reset(); }
 void OAuth2AccessTokenFetcherImpl::Start(
     const std::string& client_id,
     const std::string& client_secret,
-    const std::string& refresh_token,
     const std::vector<std::string>& scopes) {
   client_id_ = client_id;
   client_secret_ = client_secret;
-  refresh_token_ = refresh_token;
   scopes_ = scopes;
   StartGetAccessToken();
 }
diff --git a/google_apis/gaia/oauth2_access_token_fetcher_impl.h b/google_apis/gaia/oauth2_access_token_fetcher_impl.h
index e855236..8839b6c 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher_impl.h
+++ b/google_apis/gaia/oauth2_access_token_fetcher_impl.h
@@ -49,13 +49,13 @@ class OAuth2AccessTokenFetcherImpl : public OAuth2AccessTokenFetcher,
                                      public net::URLFetcherDelegate {
  public:
   OAuth2AccessTokenFetcherImpl(OAuth2AccessTokenConsumer* consumer,
-                               net::URLRequestContextGetter* getter);
+                               net::URLRequestContextGetter* getter,
+                               const std::string& refresh_token);
   virtual ~OAuth2AccessTokenFetcherImpl();
 
   // Implementation of OAuth2AccessTokenFetcher
   virtual void Start(const std::string& client_id,
                      const std::string& client_secret,
-                     const std::string& refresh_token,
                      const std::vector<std::string>& scopes) OVERRIDE;
 
   virtual void CancelRequest() OVERRIDE;
@@ -97,13 +97,13 @@ class OAuth2AccessTokenFetcherImpl : public OAuth2AccessTokenFetcher,
 
   // State that is set during construction.
   net::URLRequestContextGetter* const getter_;
+  std::string refresh_token_;
   State state_;
 
   // While a fetch is in progress.
   scoped_ptr<net::URLFetcher> fetcher_;
   std::string client_id_;
   std::string client_secret_;
-  std::string refresh_token_;
   std::vector<std::string> scopes_;
 
   friend class OAuth2AccessTokenFetcherImplTest;
diff --git a/google_apis/gaia/oauth2_access_token_fetcher_impl_unittest.cc b/google_apis/gaia/oauth2_access_token_fetcher_impl_unittest.cc
index 8bf60fe..f263932 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher_impl_unittest.cc
+++ b/google_apis/gaia/oauth2_access_token_fetcher_impl_unittest.cc
@@ -86,7 +86,7 @@ class OAuth2AccessTokenFetcherImplTest : public testing::Test {
   OAuth2AccessTokenFetcherImplTest()
       : request_context_getter_(new net::TestURLRequestContextGetter(
             base::MessageLoopProxy::current())),
-        fetcher_(&consumer_, request_context_getter_) {
+        fetcher_(&consumer_, request_context_getter_, "refresh_token") {
     base::RunLoop().RunUntilIdle();
   }
 
@@ -125,8 +125,7 @@ TEST_F(OAuth2AccessTokenFetcherImplTest,
        DISABLED_GetAccessTokenRequestFailure) {
   TestURLFetcher* url_fetcher = SetupGetAccessToken(false, 0, std::string());
   EXPECT_CALL(consumer_, OnGetTokenFailure(_)).Times(1);
-  fetcher_.Start(
-      "client_id", "client_secret", "refresh_token", ScopeList());
+  fetcher_.Start("client_id", "client_secret", ScopeList());
   fetcher_.OnURLFetchComplete(url_fetcher);
 }
 
@@ -135,8 +134,7 @@ TEST_F(OAuth2AccessTokenFetcherImplTest,
   TestURLFetcher* url_fetcher =
       SetupGetAccessToken(true, net::HTTP_FORBIDDEN, std::string());
   EXPECT_CALL(consumer_, OnGetTokenFailure(_)).Times(1);
-  fetcher_.Start(
-      "client_id", "client_secret", "refresh_token", ScopeList());
+  fetcher_.Start("client_id", "client_secret", ScopeList());
   fetcher_.OnURLFetchComplete(url_fetcher);
 }
 
@@ -144,8 +142,7 @@ TEST_F(OAuth2AccessTokenFetcherImplTest, DISABLED_Success) {
   TestURLFetcher* url_fetcher =
       SetupGetAccessToken(true, net::HTTP_OK, kValidTokenResponse);
   EXPECT_CALL(consumer_, OnGetTokenSuccess("at1", _)).Times(1);
-  fetcher_.Start(
-      "client_id", "client_secret", "refresh_token", ScopeList());
+  fetcher_.Start("client_id", "client_secret", ScopeList());
   fetcher_.OnURLFetchComplete(url_fetcher);
 }
 
diff --git a/google_apis/gaia/oauth2_api_call_flow.cc b/google_apis/gaia/oauth2_api_call_flow.cc
index 9688e5a..08312eb 100644
--- a/google_apis/gaia/oauth2_api_call_flow.cc
+++ b/google_apis/gaia/oauth2_api_call_flow.cc
@@ -109,7 +109,6 @@ void OAuth2ApiCallFlow::BeginMintAccessToken() {
   oauth2_access_token_fetcher_->Start(
       GaiaUrls::GetInstance()->oauth2_chrome_client_id(),
       GaiaUrls::GetInstance()->oauth2_chrome_client_secret(),
-      refresh_token_,
       scopes_);
 }
 
@@ -127,7 +126,7 @@ void OAuth2ApiCallFlow::EndMintAccessToken(
 }
 
 OAuth2AccessTokenFetcher* OAuth2ApiCallFlow::CreateAccessTokenFetcher() {
-  return new OAuth2AccessTokenFetcherImpl(this, context_);
+  return new OAuth2AccessTokenFetcherImpl(this, context_, refresh_token_);
 }
 
 void OAuth2ApiCallFlow::OnURLFetchComplete(const net::URLFetcher* source) {
diff --git a/google_apis/gaia/oauth2_api_call_flow_unittest.cc b/google_apis/gaia/oauth2_api_call_flow_unittest.cc
index 29202e8..754b15e 100644
--- a/google_apis/gaia/oauth2_api_call_flow_unittest.cc
+++ b/google_apis/gaia/oauth2_api_call_flow_unittest.cc
@@ -73,15 +73,15 @@ class MockUrlFetcherFactory : public ScopedURLFetcherFactory,
 class MockAccessTokenFetcher : public OAuth2AccessTokenFetcherImpl {
  public:
   MockAccessTokenFetcher(OAuth2AccessTokenConsumer* consumer,
-                         net::URLRequestContextGetter* getter)
-      : OAuth2AccessTokenFetcherImpl(consumer, getter) {}
+                         net::URLRequestContextGetter* getter,
+                         const std::string& refresh_token)
+      : OAuth2AccessTokenFetcherImpl(consumer, getter, refresh_token) {}
   ~MockAccessTokenFetcher() {}
 
-  MOCK_METHOD4(Start,
-               void (const std::string& client_id,
-                     const std::string& client_secret,
-                     const std::string& refresh_token,
-                     const std::vector<std::string>& scopes));
+  MOCK_METHOD3(Start,
+               void(const std::string& client_id,
+                    const std::string& client_secret,
+                    const std::vector<std::string>& scopes));
 };
 
 class MockApiCallFlow : public OAuth2ApiCallFlow {
@@ -110,13 +110,11 @@ class MockApiCallFlow : public OAuth2ApiCallFlow {
 
 class OAuth2ApiCallFlowTest : public testing::Test {
  protected:
-  void SetupAccessTokenFetcher(
-      const std::string& rt, const std::vector<std::string>& scopes) {
+  void SetupAccessTokenFetcher(const std::vector<std::string>& scopes) {
     EXPECT_CALL(*access_token_fetcher_,
-        Start(GaiaUrls::GetInstance()->oauth2_chrome_client_id(),
-              GaiaUrls::GetInstance()->oauth2_chrome_client_secret(),
-              rt, scopes))
-        .Times(1);
+                Start(GaiaUrls::GetInstance()->oauth2_chrome_client_id(),
+                      GaiaUrls::GetInstance()->oauth2_chrome_client_secret(),
+                      scopes)).Times(1);
     EXPECT_CALL(*flow_, CreateAccessTokenFetcher())
         .WillOnce(Return(access_token_fetcher_.release()));
   }
@@ -146,8 +144,8 @@ class OAuth2ApiCallFlowTest : public testing::Test {
             message_loop_.message_loop_proxy());
     flow_.reset(new MockApiCallFlow(
         request_context_getter, refresh_token, access_token, scopes));
-    access_token_fetcher_.reset(
-        new MockAccessTokenFetcher(flow_.get(), request_context_getter));
+    access_token_fetcher_.reset(new MockAccessTokenFetcher(
+        flow_.get(), request_context_getter, refresh_token));
   }
 
   TestURLFetcher* SetupApiCall(bool succeeds, net::HttpStatusCode status) {
@@ -188,7 +186,7 @@ TEST_F(OAuth2ApiCallFlowTest, SecondApiCallSucceeds) {
   CreateFlow(rt, at, scopes);
   TestURLFetcher* url_fetcher1 = SetupApiCall(true, net::HTTP_UNAUTHORIZED);
   flow_->Start();
-  SetupAccessTokenFetcher(rt, scopes);
+  SetupAccessTokenFetcher(scopes);
   flow_->OnURLFetchComplete(url_fetcher1);
   TestURLFetcher* url_fetcher2 = SetupApiCall(true, net::HTTP_OK);
   EXPECT_CALL(*flow_, ProcessApiCallSuccess(url_fetcher2));
@@ -206,7 +204,7 @@ TEST_F(OAuth2ApiCallFlowTest, SecondApiCallFails) {
   CreateFlow(rt, at, scopes);
   TestURLFetcher* url_fetcher1 = SetupApiCall(true, net::HTTP_UNAUTHORIZED);
   flow_->Start();
-  SetupAccessTokenFetcher(rt, scopes);
+  SetupAccessTokenFetcher(scopes);
   flow_->OnURLFetchComplete(url_fetcher1);
   TestURLFetcher* url_fetcher2 = SetupApiCall(false, net::HTTP_UNAUTHORIZED);
   EXPECT_CALL(*flow_, ProcessApiCallFailure(url_fetcher2));
@@ -224,7 +222,7 @@ TEST_F(OAuth2ApiCallFlowTest, NewTokenGenerationFails) {
   CreateFlow(rt, at, scopes);
   TestURLFetcher* url_fetcher = SetupApiCall(true, net::HTTP_UNAUTHORIZED);
   flow_->Start();
-  SetupAccessTokenFetcher(rt, scopes);
+  SetupAccessTokenFetcher(scopes);
   flow_->OnURLFetchComplete(url_fetcher);
   GoogleServiceAuthError error(
       GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS);
@@ -238,7 +236,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenFirstApiCallSucceeds) {
   std::vector<std::string> scopes(CreateTestScopes());
 
   CreateFlow(rt, std::string(), scopes);
-  SetupAccessTokenFetcher(rt, scopes);
+  SetupAccessTokenFetcher(scopes);
   TestURLFetcher* url_fetcher = SetupApiCall(true, net::HTTP_OK);
   EXPECT_CALL(*flow_, ProcessApiCallSuccess(url_fetcher));
   flow_->Start();
@@ -254,7 +252,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenApiCallFails) {
   std::vector<std::string> scopes(CreateTestScopes());
 
   CreateFlow(rt, std::string(), scopes);
-  SetupAccessTokenFetcher(rt, scopes);
+  SetupAccessTokenFetcher(scopes);
   TestURLFetcher* url_fetcher = SetupApiCall(false, net::HTTP_BAD_GATEWAY);
   EXPECT_CALL(*flow_, ProcessApiCallFailure(url_fetcher));
   flow_->Start();
@@ -270,7 +268,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenNewTokenGenerationFails) {
   std::vector<std::string> scopes(CreateTestScopes());
 
   CreateFlow(rt, std::string(), scopes);
-  SetupAccessTokenFetcher(rt, scopes);
+  SetupAccessTokenFetcher(scopes);
   GoogleServiceAuthError error(
       GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS);
   EXPECT_CALL(*flow_, ProcessMintAccessTokenFailure(error));
diff --git a/google_apis/gaia/oauth2_token_service.cc b/google_apis/gaia/oauth2_token_service.cc
index f466b8a..7a183b6 100644
--- a/google_apis/gaia/oauth2_token_service.cc
+++ b/google_apis/gaia/oauth2_token_service.cc
@@ -77,10 +77,8 @@ void OAuth2TokenService::RequestImpl::InformConsumer(
     consumer_->OnGetTokenFailure(this, error);
 }
 
-// Class that fetches an OAuth2 access token for a given set of scopes and
-// OAuth2 refresh token.
-
-// Class that fetches OAuth2 access tokens for given scopes and refresh token.
+// Class that fetches an OAuth2 access token for a given account id and set of
+// scopes.
 //
 // It aims to meet OAuth2TokenService's requirements on token fetching. Retry
 // mechanism is used to handle failures.
@@ -110,14 +108,13 @@ void OAuth2TokenService::RequestImpl::InformConsumer(
 class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
  public:
   // Creates a Fetcher and starts fetching an OAuth2 access token for
-  // |refresh_token| and |scopes| in the request context obtained by |getter|.
+  // |account_id| and |scopes| in the request context obtained by |getter|.
   // The given |oauth2_token_service| will be informed when fetching is done.
   static Fetcher* CreateAndStart(OAuth2TokenService* oauth2_token_service,
                                  const std::string& account_id,
                                  net::URLRequestContextGetter* getter,
                                  const std::string& client_id,
                                  const std::string& client_secret,
-                                 const std::string& refresh_token,
                                  const ScopeSet& scopes,
                                  base::WeakPtr<RequestImpl> waiting_request);
   virtual ~Fetcher();
@@ -135,7 +132,6 @@ class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
   void Cancel();
 
   const ScopeSet& GetScopeSet() const;
-  const std::string& GetRefreshToken() const;
   const std::string& GetClientId() const;
   const std::string& GetAccountId() const;
 
@@ -155,7 +151,6 @@ class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
           net::URLRequestContextGetter* getter,
           const std::string& client_id,
           const std::string& client_secret,
-          const std::string& refresh_token,
           const OAuth2TokenService::ScopeSet& scopes,
           base::WeakPtr<RequestImpl> waiting_request);
   void Start();
@@ -171,7 +166,6 @@ class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
   OAuth2TokenService* const oauth2_token_service_;
   scoped_refptr<net::URLRequestContextGetter> getter_;
   const std::string account_id_;
-  const std::string refresh_token_;
   const ScopeSet scopes_;
   std::vector<base::WeakPtr<RequestImpl> > waiting_requests_;
 
@@ -200,7 +194,6 @@ OAuth2TokenService::Fetcher* OAuth2TokenService::Fetcher::CreateAndStart(
     net::URLRequestContextGetter* getter,
     const std::string& client_id,
     const std::string& client_secret,
-    const std::string& refresh_token,
     const OAuth2TokenService::ScopeSet& scopes,
     base::WeakPtr<RequestImpl> waiting_request) {
   OAuth2TokenService::Fetcher* fetcher = new Fetcher(
@@ -209,7 +202,6 @@ OAuth2TokenService::Fetcher* OAuth2TokenService::Fetcher::CreateAndStart(
       getter,
       client_id,
       client_secret,
-      refresh_token,
       scopes,
       waiting_request);
   fetcher->Start();
@@ -222,13 +214,11 @@ OAuth2TokenService::Fetcher::Fetcher(
     net::URLRequestContextGetter* getter,
     const std::string& client_id,
     const std::string& client_secret,
-    const std::string& refresh_token,
     const OAuth2TokenService::ScopeSet& scopes,
     base::WeakPtr<RequestImpl> waiting_request)
     : oauth2_token_service_(oauth2_token_service),
       getter_(getter),
       account_id_(account_id),
-      refresh_token_(refresh_token),
       scopes_(scopes),
       retry_number_(0),
       error_(GoogleServiceAuthError::SERVICE_UNAVAILABLE),
@@ -236,7 +226,6 @@ OAuth2TokenService::Fetcher::Fetcher(
       client_secret_(client_secret) {
   DCHECK(oauth2_token_service_);
   DCHECK(getter_.get());
-  DCHECK(refresh_token_.length());
   waiting_requests_.push_back(waiting_request);
 }
 
@@ -247,10 +236,11 @@ OAuth2TokenService::Fetcher::~Fetcher() {
 }
 
 void OAuth2TokenService::Fetcher::Start() {
-  fetcher_.reset(new OAuth2AccessTokenFetcherImpl(this, getter_.get()));
+  fetcher_.reset(oauth2_token_service_->CreateAccessTokenFetcher(
+      account_id_, getter_.get(), this));
+  DCHECK(fetcher_);
   fetcher_->Start(client_id_,
                   client_secret_,
-                  refresh_token_,
                   std::vector<std::string>(scopes_.begin(), scopes_.end()));
   retry_timer_.Stop();
 }
@@ -356,10 +346,6 @@ const OAuth2TokenService::ScopeSet& OAuth2TokenService::Fetcher::GetScopeSet()
   return scopes_;
 }
 
-const std::string& OAuth2TokenService::Fetcher::GetRefreshToken() const {
-  return refresh_token_;
-}
-
 const std::string& OAuth2TokenService::Fetcher::GetClientId() const {
   return client_id_;
 }
@@ -406,12 +392,6 @@ void OAuth2TokenService::RemoveDiagnosticsObserver(
   diagnostics_observer_list_.RemoveObserver(observer);
 }
 
-bool OAuth2TokenService::RefreshTokenIsAvailable(
-    const std::string& account_id) const {
-  DCHECK(CalledOnValidThread());
-  return !GetRefreshToken(account_id).empty();
-}
-
 std::vector<std::string> OAuth2TokenService::GetAccounts() {
   return std::vector<std::string>();
 }
@@ -515,8 +495,6 @@ void OAuth2TokenService::FetchOAuth2Token(RequestImpl* request,
                                           const std::string& client_id,
                                           const std::string& client_secret,
                                           const ScopeSet& scopes) {
-  std::string refresh_token = GetRefreshToken(account_id);
-
   // If there is already a pending fetcher for |scopes| and |account_id|,
   // simply register this |request| for those results rather than starting
   // a new fetcher.
@@ -536,7 +514,6 @@ void OAuth2TokenService::FetchOAuth2Token(RequestImpl* request,
                               getter,
                               client_id,
                               client_secret,
-                              refresh_token,
                               scopes,
                               request->AsWeakPtr());
 }
diff --git a/google_apis/gaia/oauth2_token_service.h b/google_apis/gaia/oauth2_token_service.h
index 013e784..685b9db 100644
--- a/google_apis/gaia/oauth2_token_service.h
+++ b/google_apis/gaia/oauth2_token_service.h
@@ -26,6 +26,7 @@ class URLRequestContextGetter;
 }
 
 class GoogleServiceAuthError;
+class OAuth2AccessTokenFetcher;
 
 // Abstract base class for a service that fetches and caches OAuth2 access
 // tokens. Concrete subclasses should implement GetRefreshToken to return
@@ -172,7 +173,7 @@ class OAuth2TokenService : public base::NonThreadSafe {
 
   // Returns true if a refresh token exists for |account_id|. If false, calls to
   // |StartRequest| will result in a Consumer::OnGetTokenFailure callback.
-  virtual bool RefreshTokenIsAvailable(const std::string& account_id) const;
+  virtual bool RefreshTokenIsAvailable(const std::string& account_id) const = 0;
 
   // Mark an OAuth2 |access_token| issued for |account_id| and |scopes| as
   // invalid. This should be done if the token was received from this class,
@@ -228,10 +229,6 @@ class OAuth2TokenService : public base::NonThreadSafe {
     Consumer* const consumer_;
   };
 
-  // Subclasses should return the maintained refresh token for |account_id|.
-  // If no token is available, return an empty string.
-  virtual std::string GetRefreshToken(const std::string& account_id) const = 0;
-
   // Subclasses can override if they want to report errors to the user.
   virtual void UpdateAuthError(
       const std::string& account_id,
@@ -274,6 +271,16 @@ class OAuth2TokenService : public base::NonThreadSafe {
                                 const std::string& client_secret,
                                 const ScopeSet& scopes);
 
+  // Creates an access token fetcher for the given account id.
+  //
+  // Subclasses should override to create an access token fetcher for the given
+  // |account_id|. This method is only called if subclasses use the default
+  // implementation of |FetchOAuth2Token|.
+  virtual OAuth2AccessTokenFetcher* CreateAccessTokenFetcher(
+      const std::string& account_id,
+      net::URLRequestContextGetter* getter,
+      OAuth2AccessTokenConsumer* consumer) = 0;
+
   // Invalidates the |access_token| issued for |account_id|, |client_id| and
   // |scopes|. Virtual so it can be overriden for tests and for platform-
   // specifc behavior.
diff --git a/google_apis/gaia/oauth2_token_service_unittest.cc b/google_apis/gaia/oauth2_token_service_unittest.cc
index c2ae5f8..b79e361 100644
--- a/google_apis/gaia/oauth2_token_service_unittest.cc
+++ b/google_apis/gaia/oauth2_token_service_unittest.cc
@@ -9,6 +9,7 @@
 #include "google_apis/gaia/gaia_constants.h"
 #include "google_apis/gaia/google_service_auth_error.h"
 #include "google_apis/gaia/oauth2_access_token_consumer.h"
+#include "google_apis/gaia/oauth2_access_token_fetcher_impl.h"
 #include "google_apis/gaia/oauth2_token_service.h"
 #include "google_apis/gaia/oauth2_token_service_test_util.h"
 #include "net/http/http_status_code.h"
@@ -55,18 +56,19 @@ class TestOAuth2TokenService : public OAuth2TokenService {
   // For testing: set the refresh token to be used.
   void set_refresh_token(const std::string& account_id,
                          const std::string& refresh_token) {
-    refresh_tokens_[account_id] = refresh_token;
+    if (refresh_token.empty())
+      refresh_tokens_.erase(account_id);
+    else
+      refresh_tokens_[account_id] = refresh_token;
   }
 
- protected:
-  virtual std::string GetRefreshToken(const std::string& account_id)
-      const OVERRIDE {
+  virtual bool RefreshTokenIsAvailable(const std::string& account_id) const
+      OVERRIDE {
     std::map<std::string, std::string>::const_iterator it =
         refresh_tokens_.find(account_id);
-    if (it != refresh_tokens_.end())
-      return it->second;
-    return std::string();
-  }
+
+    return it != refresh_tokens_.end();
+  };
 
  private:
   // OAuth2TokenService implementation.
@@ -74,6 +76,17 @@ class TestOAuth2TokenService : public OAuth2TokenService {
     return request_context_getter_.get();
   }
 
+  virtual OAuth2AccessTokenFetcher* CreateAccessTokenFetcher(
+      const std::string& account_id,
+      net::URLRequestContextGetter* getter,
+      OAuth2AccessTokenConsumer* consumer) OVERRIDE {
+    std::map<std::string, std::string>::const_iterator it =
+        refresh_tokens_.find(account_id);
+    DCHECK(it != refresh_tokens_.end());
+    std::string refresh_token(it->second);
+    return new OAuth2AccessTokenFetcherImpl(consumer, getter, refresh_token);
+  };
+
   std::map<std::string, std::string> refresh_tokens_;
   scoped_refptr<net::TestURLRequestContextGetter> request_context_getter_;
 };