Handling of multiple concurrent requests from different clients in OAuth2TokenService

BUG=268937
TEST=OAuth2TokenServiceTest.SameScopesRequestedForDifferentClients
TBR=tim (for chrome/browser/sync)

Review URL: https://chromiumcodereview.appspot.com/22581003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221303 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 348 insertions, 89 deletions

diff --git a/google_apis/gaia/oauth2_access_token_fetcher.cc b/google_apis/gaia/oauth2_access_token_fetcher.cc
index 456251f..9fd46d7 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher.cc
+++ b/google_apis/gaia/oauth2_access_token_fetcher.cc
@@ -56,13 +56,14 @@ static GoogleServiceAuthError CreateAuthError(URLRequestStatus status) {
   }
 }
 
-static URLFetcher* CreateFetcher(URLRequestContextGetter* getter,
+static URLFetcher* CreateFetcher(int id,
+                                 URLRequestContextGetter* getter,
                                  const GURL& url,
                                  const std::string& body,
                                  URLFetcherDelegate* delegate) {
   bool empty_body = body.empty();
   URLFetcher* result = net::URLFetcher::Create(
-      0, url,
+      id, url,
       empty_body ? URLFetcher::GET : URLFetcher::POST,
       delegate);
 
@@ -82,6 +83,8 @@ static URLFetcher* CreateFetcher(URLRequestContextGetter* getter,
 }
 }  // namespace
 
+int OAuth2AccessTokenFetcher::last_fetcher_id_ = 0;
+
 OAuth2AccessTokenFetcher::OAuth2AccessTokenFetcher(
     OAuth2AccessTokenConsumer* consumer,
     URLRequestContextGetter* getter)
@@ -110,6 +113,7 @@ void OAuth2AccessTokenFetcher::StartGetAccessToken() {
   CHECK_EQ(INITIAL, state_);
   state_ = GET_ACCESS_TOKEN_STARTED;
   fetcher_.reset(CreateFetcher(
+      last_fetcher_id_++,
       getter_,
       MakeGetAccessTokenUrl(),
       MakeGetAccessTokenBody(
@@ -231,3 +235,8 @@ bool OAuth2AccessTokenFetcher::ParseGetAccessTokenResponse(
   return dict->GetString(kAccessTokenKey, access_token) &&
       dict->GetInteger(kExpiresInKey, expires_in);
 }
+
+// static
+void OAuth2AccessTokenFetcher::ResetLastFetcherIdForTest() {
+  last_fetcher_id_ = 0;
+}
diff --git a/google_apis/gaia/oauth2_access_token_fetcher.h b/google_apis/gaia/oauth2_access_token_fetcher.h
index 11ac6ea..e9e1520 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher.h
+++ b/google_apis/gaia/oauth2_access_token_fetcher.h
@@ -26,6 +26,10 @@ class URLRequestContextGetter;
 class URLRequestStatus;
 }
 
+namespace policy {
+  class UserPolicySigninServiceTest;
+}
+
 // Abstracts the details to get OAuth2 access token token from
 // OAuth2 refresh token.
 // See "Using the Refresh Token" section in:
@@ -94,6 +98,9 @@ class OAuth2AccessTokenFetcher : public net::URLFetcherDelegate {
                                           std::string* access_token,
                                           int* expires_in);
 
+  // Resets |last_fetcher_id_| to 0.
+  static void ResetLastFetcherIdForTest();
+
   // State that is set during construction.
   OAuth2AccessTokenConsumer* const consumer_;
   net::URLRequestContextGetter* const getter_;
@@ -106,7 +113,12 @@ class OAuth2AccessTokenFetcher : public net::URLFetcherDelegate {
   std::string refresh_token_;
   std::vector<std::string> scopes_;
 
+  // The last fetcher id.
+  static int last_fetcher_id_;
+
   friend class OAuth2AccessTokenFetcherTest;
+  friend class OAuth2TokenServiceTest;
+  friend class policy::UserPolicySigninServiceTest;
   FRIEND_TEST_ALL_PREFIXES(OAuth2AccessTokenFetcherTest,
                            ParseGetAccessTokenResponse);
   FRIEND_TEST_ALL_PREFIXES(OAuth2AccessTokenFetcherTest,
diff --git a/google_apis/gaia/oauth2_token_service.cc b/google_apis/gaia/oauth2_token_service.cc
index 0834c60..828f4cc6 100644
--- a/google_apis/gaia/oauth2_token_service.cc
+++ b/google_apis/gaia/oauth2_token_service.cc
@@ -15,12 +15,57 @@
 #include "base/timer/timer.h"
 #include "google_apis/gaia/gaia_urls.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.h"
 #include "net/url_request/url_request_context_getter.h"
 
 int OAuth2TokenService::max_fetch_retry_num_ = 5;
 
+OAuth2TokenService::ClientScopeSet::ClientScopeSet(
+    const std::string& client_id,
+    const ScopeSet& scopes)
+    : client_id(client_id),
+      scopes(scopes) {
+}
+
+OAuth2TokenService::ClientScopeSet::~ClientScopeSet() {
+}
+
+bool OAuth2TokenService::ClientScopeSet::operator<(
+    const ClientScopeSet& s) const {
+  if (client_id < s.client_id)
+    return true;
+  else if (s.client_id < client_id)
+    return false;
+
+  return scopes < s.scopes;
+}
+
+OAuth2TokenService::FetchParameters::FetchParameters(
+    const std::string& client_id,
+    const std::string& refresh_token,
+    const ScopeSet& scopes)
+    : client_id(client_id),
+      refresh_token(refresh_token),
+      scopes(scopes) {
+}
+
+OAuth2TokenService::FetchParameters::~FetchParameters() {
+}
+
+bool OAuth2TokenService::FetchParameters::operator<(
+    const FetchParameters& p) const {
+  if (client_id < p.client_id)
+    return true;
+  else if (p.client_id < client_id)
+    return false;
+
+  if (refresh_token < p.refresh_token)
+    return true;
+  else if (p.refresh_token < refresh_token)
+    return false;
+
+  return scopes < p.scopes;
+}
+
 OAuth2TokenService::RequestImpl::RequestImpl(
     OAuth2TokenService::Consumer* consumer)
     : consumer_(consumer) {
@@ -41,6 +86,9 @@ 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.
 //
 // It aims to meet OAuth2TokenService's requirements on token fetching. Retry
@@ -57,17 +105,17 @@ void OAuth2TokenService::RequestImpl::InformConsumer(
 //
 // Requests that are waiting for the fetching results of this Fetcher can be
 // added to the Fetcher by calling
-// OAuth2TokenService::Fetcher::AddWaitingRequest() before the Fetcher completes
-// fetching.
+// OAuth2TokenService::Fetcher::AddWaitingRequest() before the Fetcher
+// completes fetching.
 //
-// The waiting requests are taken as weak pointers and they can be deleted. The
-// waiting requests will be called back with fetching results if they are not
-// deleted
+// The waiting requests are taken as weak pointers and they can be deleted.
+// The waiting requests will be called back with fetching results if they are
+// not deleted
 // - when the Fetcher completes fetching, if the Fetcher is not destructed
 //   before it completes fetching, or
 // - when the Fetcher is destructed if the Fetcher is destructed before it
-//   completes fetching (in this case, the waiting requests will be called back
-//   with error).
+//   completes fetching (in this case, the waiting requests will be called
+//   back with error).
 class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
  public:
   // Creates a Fetcher and starts fetching an OAuth2 access token for
@@ -75,20 +123,24 @@ class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
   // The given |oauth2_token_service| will be informed when fetching is done.
   static Fetcher* CreateAndStart(OAuth2TokenService* oauth2_token_service,
                                  net::URLRequestContextGetter* getter,
-                                 const std::string& chrome_client_id,
-                                 const std::string& chrome_client_secret,
+                                 const std::string& client_id,
+                                 const std::string& client_secret,
                                  const std::string& refresh_token,
-                                 const OAuth2TokenService::ScopeSet& scopes,
+                                 const ScopeSet& scopes,
                                  base::WeakPtr<RequestImpl> waiting_request);
   virtual ~Fetcher();
 
   // Add a request that is waiting for the result of this Fetcher.
   void AddWaitingRequest(base::WeakPtr<RequestImpl> waiting_request);
 
+  // Returns count of waiting requests.
+  size_t GetWaitingRequestCount() const;
+
   void Cancel();
 
-  const OAuth2TokenService::ScopeSet& GetScopeSet() const;
+  const ScopeSet& GetScopeSet() const;
   const std::string& GetRefreshToken() const;
+  const std::string& GetClientId() const;
 
   // The error result from this fetcher.
   const GoogleServiceAuthError& error() const { return error_; }
@@ -97,13 +149,14 @@ class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
    // OAuth2AccessTokenConsumer
   virtual void OnGetTokenSuccess(const std::string& access_token,
                                  const base::Time& expiration_date) OVERRIDE;
-  virtual void OnGetTokenFailure(const GoogleServiceAuthError& error) OVERRIDE;
+  virtual void OnGetTokenFailure(
+      const GoogleServiceAuthError& error) OVERRIDE;
 
  private:
   Fetcher(OAuth2TokenService* oauth2_token_service,
           net::URLRequestContextGetter* getter,
-          const std::string& chrome_client_id,
-          const std::string& chrome_client_secret,
+          const std::string& client_id,
+          const std::string& client_secret,
           const std::string& refresh_token,
           const OAuth2TokenService::ScopeSet& scopes,
           base::WeakPtr<RequestImpl> waiting_request);
@@ -120,11 +173,11 @@ class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
   OAuth2TokenService* const oauth2_token_service_;
   scoped_refptr<net::URLRequestContextGetter> getter_;
   const std::string refresh_token_;
-  const OAuth2TokenService::ScopeSet scopes_;
+  const ScopeSet scopes_;
   std::vector<base::WeakPtr<RequestImpl> > waiting_requests_;
 
   int retry_number_;
-  base::OneShotTimer<OAuth2TokenService::Fetcher> retry_timer_;
+  base::OneShotTimer<Fetcher> retry_timer_;
   scoped_ptr<OAuth2AccessTokenFetcher> fetcher_;
 
   // Variables that store fetch results.
@@ -133,9 +186,10 @@ class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
   GoogleServiceAuthError error_;
   std::string access_token_;
   base::Time expiration_date_;
+
   // OAuth2 client id and secret.
-  std::string chrome_client_id_;
-  std::string chrome_client_secret_;
+  std::string client_id_;
+  std::string client_secret_;
 
   DISALLOW_COPY_AND_ASSIGN(Fetcher);
 };
@@ -144,16 +198,16 @@ class OAuth2TokenService::Fetcher : public OAuth2AccessTokenConsumer {
 OAuth2TokenService::Fetcher* OAuth2TokenService::Fetcher::CreateAndStart(
     OAuth2TokenService* oauth2_token_service,
     net::URLRequestContextGetter* getter,
-    const std::string& chrome_client_id,
-    const std::string& chrome_client_secret,
+    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(
       oauth2_token_service,
       getter,
-      chrome_client_id,
-      chrome_client_secret,
+      client_id,
+      client_secret,
       refresh_token,
       scopes,
       waiting_request);
@@ -164,8 +218,8 @@ OAuth2TokenService::Fetcher* OAuth2TokenService::Fetcher::CreateAndStart(
 OAuth2TokenService::Fetcher::Fetcher(
     OAuth2TokenService* oauth2_token_service,
     net::URLRequestContextGetter* getter,
-    const std::string& chrome_client_id,
-    const std::string& chrome_client_secret,
+    const std::string& client_id,
+    const std::string& client_secret,
     const std::string& refresh_token,
     const OAuth2TokenService::ScopeSet& scopes,
     base::WeakPtr<RequestImpl> waiting_request)
@@ -175,8 +229,8 @@ OAuth2TokenService::Fetcher::Fetcher(
       scopes_(scopes),
       retry_number_(0),
       error_(GoogleServiceAuthError::SERVICE_UNAVAILABLE),
-      chrome_client_id_(chrome_client_id),
-      chrome_client_secret_(chrome_client_secret) {
+      client_id_(client_id),
+      client_secret_(client_secret) {
   DCHECK(oauth2_token_service_);
   DCHECK(getter_.get());
   DCHECK(refresh_token_.length());
@@ -191,8 +245,8 @@ OAuth2TokenService::Fetcher::~Fetcher() {
 
 void OAuth2TokenService::Fetcher::Start() {
   fetcher_.reset(new OAuth2AccessTokenFetcher(this, getter_.get()));
-  fetcher_->Start(chrome_client_id_,
-                  chrome_client_secret_,
+  fetcher_->Start(client_id_,
+                  client_secret_,
                   refresh_token_,
                   std::vector<std::string>(scopes_.begin(), scopes_.end()));
   retry_timer_.Stop();
@@ -212,7 +266,8 @@ void OAuth2TokenService::Fetcher::OnGetTokenSuccess(
   // we still inform all waiting Consumers of a successful token fetch below.
   // This is intentional -- some consumers may need the token for cleanup
   // tasks. https://chromiumcodereview.appspot.com/11312124/
-  oauth2_token_service_->RegisterCacheEntry(refresh_token_,
+  oauth2_token_service_->RegisterCacheEntry(client_id_,
+                                            refresh_token_,
                                             scopes_,
                                             access_token_,
                                             expiration_date_);
@@ -281,6 +336,10 @@ void OAuth2TokenService::Fetcher::AddWaitingRequest(
   waiting_requests_.push_back(waiting_request);
 }
 
+size_t OAuth2TokenService::Fetcher::GetWaitingRequestCount() const {
+  return waiting_requests_.size();
+}
+
 void OAuth2TokenService::Fetcher::Cancel() {
   fetcher_.reset();
   retry_timer_.Stop();
@@ -297,6 +356,10 @@ const std::string& OAuth2TokenService::Fetcher::GetRefreshToken() const {
   return refresh_token_;
 }
 
+const std::string& OAuth2TokenService::Fetcher::GetClientId() const {
+  return client_id_;
+}
+
 OAuth2TokenService::Request::Request() {
 }
 
@@ -389,8 +452,9 @@ OAuth2TokenService::StartRequestForClientWithContext(
     return request.PassAs<Request>();
   }
 
-  if (HasCacheEntry(scopes)) {
-    StartCacheLookupRequest(request.get(), scopes, consumer);
+  ClientScopeSet client_scopes(client_id, scopes);
+  if (HasCacheEntry(client_scopes)) {
+    StartCacheLookupRequest(request.get(), client_scopes, consumer);
   } else {
     FetchOAuth2Token(request.get(),
                      getter,
@@ -411,7 +475,9 @@ void OAuth2TokenService::FetchOAuth2Token(RequestImpl* request,
   // If there is already a pending fetcher for |scopes| and |refresh_token|,
   // simply register this |request| for those results rather than starting
   // a new fetcher.
-  FetchParameters fetch_parameters = std::make_pair(refresh_token, scopes);
+  FetchParameters fetch_parameters = FetchParameters(client_id,
+                                                     refresh_token,
+                                                     scopes);
   std::map<FetchParameters, Fetcher*>::iterator iter =
       pending_fetchers_.find(fetch_parameters);
   if (iter != pending_fetchers_.end()) {
@@ -431,10 +497,10 @@ void OAuth2TokenService::FetchOAuth2Token(RequestImpl* request,
 
 void OAuth2TokenService::StartCacheLookupRequest(
     RequestImpl* request,
-    const OAuth2TokenService::ScopeSet& scopes,
+    const OAuth2TokenService::ClientScopeSet& client_scopes,
     OAuth2TokenService::Consumer* consumer) {
-  CHECK(HasCacheEntry(scopes));
-  const CacheEntry* cache_entry = GetCacheEntry(scopes);
+  CHECK(HasCacheEntry(client_scopes));
+  const CacheEntry* cache_entry = GetCacheEntry(client_scopes);
   base::MessageLoop::current()->PostTask(FROM_HERE, base::Bind(
       &RequestImpl::InformConsumer,
       request->AsWeakPtr(),
@@ -446,7 +512,10 @@ void OAuth2TokenService::StartCacheLookupRequest(
 void OAuth2TokenService::InvalidateToken(const ScopeSet& scopes,
                                          const std::string& invalid_token) {
   DCHECK(CalledOnValidThread());
-  RemoveCacheEntry(scopes, invalid_token);
+  RemoveCacheEntry(
+      ClientScopeSet(GaiaUrls::GetInstance()->oauth2_chrome_client_id(),
+                     scopes),
+      invalid_token);
 }
 
 void OAuth2TokenService::OnFetchComplete(Fetcher* fetcher) {
@@ -483,23 +552,25 @@ void OAuth2TokenService::OnFetchComplete(Fetcher* fetcher) {
   // Then by (2), |fetcher| is recorded in |pending_fetchers_|.
   // Then by (3), |fetcher_| is mapped to its refresh token and ScopeSet.
   std::map<FetchParameters, Fetcher*>::iterator iter =
-    pending_fetchers_.find(std::make_pair(
-        fetcher->GetRefreshToken(), fetcher->GetScopeSet()));
+    pending_fetchers_.find(FetchParameters(
+        fetcher->GetClientId(),
+        fetcher->GetRefreshToken(),
+        fetcher->GetScopeSet()));
   DCHECK(iter != pending_fetchers_.end());
   DCHECK_EQ(fetcher, iter->second);
   pending_fetchers_.erase(iter);
 }
 
 bool OAuth2TokenService::HasCacheEntry(
-    const OAuth2TokenService::ScopeSet& scopes) {
-  const CacheEntry* cache_entry = GetCacheEntry(scopes);
+    const ClientScopeSet& client_scopes) {
+  const CacheEntry* cache_entry = GetCacheEntry(client_scopes);
   return cache_entry && cache_entry->access_token.length();
 }
 
 const OAuth2TokenService::CacheEntry* OAuth2TokenService::GetCacheEntry(
-    const OAuth2TokenService::ScopeSet& scopes) {
+    const ClientScopeSet& client_scopes) {
   DCHECK(CalledOnValidThread());
-  TokenCache::iterator token_iterator = token_cache_.find(scopes);
+  TokenCache::iterator token_iterator = token_cache_.find(client_scopes);
   if (token_iterator == token_cache_.end())
     return NULL;
   if (token_iterator->second.expiration_date <= base::Time::Now()) {
@@ -510,10 +581,10 @@ const OAuth2TokenService::CacheEntry* OAuth2TokenService::GetCacheEntry(
 }
 
 bool OAuth2TokenService::RemoveCacheEntry(
-    const OAuth2TokenService::ScopeSet& scopes,
+    const ClientScopeSet& client_scopes,
     const std::string& token_to_remove) {
   DCHECK(CalledOnValidThread());
-  TokenCache::iterator token_iterator = token_cache_.find(scopes);
+  TokenCache::iterator token_iterator = token_cache_.find(client_scopes);
   if (token_iterator != token_cache_.end() &&
       token_iterator->second.access_token == token_to_remove) {
     token_cache_.erase(token_iterator);
@@ -523,13 +594,15 @@ bool OAuth2TokenService::RemoveCacheEntry(
 }
 
 void OAuth2TokenService::RegisterCacheEntry(
+    const std::string& client_id,
     const std::string& refresh_token,
     const OAuth2TokenService::ScopeSet& scopes,
     const std::string& access_token,
     const base::Time& expiration_date) {
   DCHECK(CalledOnValidThread());
 
-  CacheEntry& token = token_cache_[scopes];
+  CacheEntry& token = token_cache_[ClientScopeSet(client_id,
+                                                  scopes)];
   token.access_token = access_token;
   token.expiration_date = expiration_date;
 }
@@ -561,7 +634,7 @@ void OAuth2TokenService::CancelRequestsForToken(
            pending_fetchers_.begin();
        iter != pending_fetchers_.end();
        ++iter) {
-    if (iter->first.first == refresh_token)
+    if (iter->first.refresh_token == refresh_token)
       fetchers_to_cancel.push_back(iter->second);
   }
   CancelFetchers(fetchers_to_cancel);
@@ -606,3 +679,16 @@ void OAuth2TokenService::set_max_authorization_token_fetch_retries_for_testing(
   DCHECK(CalledOnValidThread());
   max_fetch_retry_num_ = max_retries;
 }
+
+size_t OAuth2TokenService::GetNumPendingRequestsForTesting(
+    const std::string& client_id,
+    const std::string& refresh_token,
+    const ScopeSet& scopes) const {
+  PendingFetcherMap::const_iterator iter = pending_fetchers_.find(
+      OAuth2TokenService::FetchParameters(
+          client_id,
+          refresh_token,
+          scopes));
+  return iter == pending_fetchers_.end() ?
+             0 : iter->second->GetWaitingRequestCount();
+}
diff --git a/google_apis/gaia/oauth2_token_service.h b/google_apis/gaia/oauth2_token_service.h
index 967dc93..b58c563 100644
--- a/google_apis/gaia/oauth2_token_service.h
+++ b/google_apis/gaia/oauth2_token_service.h
@@ -10,12 +10,16 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time/time.h"
+#include "base/timer/timer.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.h"
 
 namespace net {
 class URLRequestContextGetter;
@@ -145,8 +149,23 @@ class OAuth2TokenService : public base::NonThreadSafe {
   // Return the current number of entries in the cache.
   int cache_size_for_testing() const;
   void set_max_authorization_token_fetch_retries_for_testing(int max_retries);
+  // Returns the current number of pending fetchers matching given params.
+  size_t GetNumPendingRequestsForTesting(
+      const std::string& client_id,
+      const std::string& refresh_token,
+      const ScopeSet& scopes) const;
 
  protected:
+  struct ClientScopeSet {
+    ClientScopeSet(const std::string& client_id,
+                   const ScopeSet& scopes);
+    ~ClientScopeSet();
+    bool operator<(const ClientScopeSet& set) const;
+
+    std::string client_id;
+    ScopeSet scopes;
+  };
+
   // Implements a cancelable |OAuth2TokenService::Request|, which should be
   // operated on the UI thread.
   // TODO(davidroche): move this out of header file.
@@ -178,19 +197,20 @@ class OAuth2TokenService : public base::NonThreadSafe {
   // Add a new entry to the cache.
   // Subclasses can override if there are implementation-specific reasons
   // that an access token should ever not be cached.
-  virtual void RegisterCacheEntry(const std::string& refresh_token,
+  virtual void RegisterCacheEntry(const std::string& client_id,
+                                  const std::string& refresh_token,
                                   const ScopeSet& scopes,
                                   const std::string& access_token,
                                   const base::Time& expiration_date);
 
   // Returns true if GetCacheEntry would return a valid cache entry for the
   // given scopes.
-  bool HasCacheEntry(const ScopeSet& scopes);
+  bool HasCacheEntry(const ClientScopeSet& client_scopes);
 
   // Posts a task to fire the Consumer callback with the cached token.  Must
   // Must only be called if HasCacheEntry() returns true.
   void StartCacheLookupRequest(RequestImpl* request,
-                               const ScopeSet& scopes,
+                               const ClientScopeSet& client_scopes,
                                Consumer* consumer);
 
   // Clears the internal token cache.
@@ -208,10 +228,6 @@ class OAuth2TokenService : public base::NonThreadSafe {
   void FireRefreshTokensLoaded();
   void FireRefreshTokensCleared();
 
-  // Derived classes must provide a request context used for fetching access
-  // tokens with the |StartRequest| method.
-  virtual net::URLRequestContextGetter* GetRequestContext() = 0;
-
   // Fetches an OAuth token for the specified client/scopes. Virtual so it can
   // be overridden for tests and for platform-specific behavior on Android.
   virtual void FetchOAuth2Token(RequestImpl* request,
@@ -219,13 +235,32 @@ class OAuth2TokenService : public base::NonThreadSafe {
                                 const std::string& client_id,
                                 const std::string& client_secret,
                                 const ScopeSet& scopes);
-
  private:
-  // Class that fetches an OAuth2 access token for a given set of scopes and
-  // OAuth2 refresh token.
   class Fetcher;
   friend class Fetcher;
 
+  // The parameters used to fetch an OAuth2 access token.
+  struct FetchParameters {
+    FetchParameters(const std::string& client_id,
+                    const std::string& refresh_token,
+                    const ScopeSet& scopes);
+    ~FetchParameters();
+    bool operator<(const FetchParameters& params) const;
+
+    // OAuth2 client id.
+    std::string client_id;
+    // Refresh token used for minting access tokens within this request.
+    std::string refresh_token;
+    // URL scopes for the requested access token.
+    ScopeSet scopes;
+  };
+
+  typedef std::map<FetchParameters, Fetcher*> PendingFetcherMap;
+
+  // Derived classes must provide a request context used for fetching access
+  // tokens with the |StartRequest| method.
+  virtual net::URLRequestContextGetter* GetRequestContext() = 0;
+
   // Struct that contains the information of an OAuth2 access token.
   struct CacheEntry {
     std::string access_token;
@@ -244,14 +279,14 @@ class OAuth2TokenService : public base::NonThreadSafe {
 
   // Returns a currently valid OAuth2 access token for the given set of scopes,
   // or NULL if none have been cached. Note the user of this method should
-  // ensure no entry with the same |scopes| is added before the usage of the
-  // returned entry is done.
-  const CacheEntry* GetCacheEntry(const ScopeSet& scopes);
+  // ensure no entry with the same |client_scopes| is added before the usage of
+  // the returned entry is done.
+  const CacheEntry* GetCacheEntry(const ClientScopeSet& client_scopes);
 
 
   // Removes an access token for the given set of scopes from the cache.
   // Returns true if the entry was removed, otherwise false.
-  bool RemoveCacheEntry(const OAuth2TokenService::ScopeSet& scopes,
+  bool RemoveCacheEntry(const ClientScopeSet& client_scopes,
                         const std::string& token_to_remove);
 
 
@@ -262,15 +297,12 @@ class OAuth2TokenService : public base::NonThreadSafe {
   void CancelFetchers(std::vector<Fetcher*> fetchers_to_cancel);
 
   // The cache of currently valid tokens.
-  typedef std::map<ScopeSet, CacheEntry> TokenCache;
+  typedef std::map<ClientScopeSet, CacheEntry> TokenCache;
   TokenCache token_cache_;
 
-  // The parameters (refresh token and scope set) used to fetch an OAuth2 access
-  // token.
-  typedef std::pair<std::string, ScopeSet> FetchParameters;
   // A map from fetch parameters to a fetcher that is fetching an OAuth2 access
   // token using these parameters.
-  std::map<FetchParameters, Fetcher*> pending_fetchers_;
+  PendingFetcherMap pending_fetchers_;
 
   // List of observers to notify when token availability changes.
   // Makes sure list is empty on destruction.
@@ -279,6 +311,11 @@ class OAuth2TokenService : public base::NonThreadSafe {
   // Maximum number of retries in fetching an OAuth2 access token.
   static int max_fetch_retry_num_;
 
+  FRIEND_TEST_ALL_PREFIXES(OAuth2TokenServiceTest, ClientScopeSetOrderTest);
+  FRIEND_TEST_ALL_PREFIXES(OAuth2TokenServiceTest, FetchParametersOrderTest);
+  FRIEND_TEST_ALL_PREFIXES(OAuth2TokenServiceTest,
+                           SameScopesRequestedForDifferentClients);
+
   DISALLOW_COPY_AND_ASSIGN(OAuth2TokenService);
 };
 
diff --git a/google_apis/gaia/oauth2_token_service_unittest.cc b/google_apis/gaia/oauth2_token_service_unittest.cc
index 9937268..8f4e922 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.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"
@@ -78,6 +79,7 @@ class OAuth2TokenServiceTest : public testing::Test {
   virtual void TearDown() OVERRIDE {
     // Makes sure that all the clean up tasks are run.
     base::RunLoop().RunUntilIdle();
+    OAuth2AccessTokenFetcher::ResetLastFetcherIdForTest();
   }
 
  protected:
@@ -105,7 +107,7 @@ TEST_F(OAuth2TokenServiceTest, FailureShouldNotRetry) {
   EXPECT_EQ(0, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
   fetcher->SetResponseString(std::string());
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -123,7 +125,7 @@ TEST_F(OAuth2TokenServiceTest, SuccessWithoutCaching) {
   EXPECT_EQ(0, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token", 3600));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -152,7 +154,7 @@ TEST_F(OAuth2TokenServiceTest, SuccessWithCaching) {
   EXPECT_EQ(0, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token", 3600));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -167,7 +169,7 @@ TEST_F(OAuth2TokenServiceTest, SuccessWithCaching) {
   base::RunLoop().RunUntilIdle();
 
   // No new network fetcher.
-  EXPECT_EQ(fetcher, factory_.GetFetcherByID(0));
+  EXPECT_EQ(1U, factory_.GetFetcherCount());
   EXPECT_EQ(2, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   EXPECT_EQ("token", consumer_.last_token_);
@@ -178,8 +180,9 @@ TEST_F(OAuth2TokenServiceTest, SuccessWithCaching) {
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(2, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
-  fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_EQ(2U, factory_.GetFetcherCount());
+  fetcher = factory_.GetFetcherByID(1);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token2", 3600));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -198,7 +201,7 @@ TEST_F(OAuth2TokenServiceTest, SuccessAndExpirationAndFailure) {
   EXPECT_EQ(0, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token", 0));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -214,8 +217,9 @@ TEST_F(OAuth2TokenServiceTest, SuccessAndExpirationAndFailure) {
   EXPECT_EQ(0, consumer_.number_of_errors_);
 
   // Network failure.
-  fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_EQ(2U, factory_.GetFetcherCount());
+  fetcher = factory_.GetFetcherByID(1);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
   fetcher->SetResponseString(std::string());
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -233,7 +237,7 @@ TEST_F(OAuth2TokenServiceTest, SuccessAndExpirationAndSuccess) {
   EXPECT_EQ(0, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token", 0));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -248,8 +252,9 @@ TEST_F(OAuth2TokenServiceTest, SuccessAndExpirationAndSuccess) {
   EXPECT_EQ(1, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
 
-  fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_EQ(2U, factory_.GetFetcherCount());
+  fetcher = factory_.GetFetcherByID(1);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("another token", 0));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -267,7 +272,7 @@ TEST_F(OAuth2TokenServiceTest, RequestDeletedBeforeCompletion) {
   EXPECT_EQ(0, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_TRUE(fetcher);
 
   request.reset();
 
@@ -285,6 +290,7 @@ TEST_F(OAuth2TokenServiceTest, RequestDeletedAfterCompletion) {
       std::set<std::string>(), &consumer_));
   base::RunLoop().RunUntilIdle();
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token", 3600));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -312,6 +318,7 @@ TEST_F(OAuth2TokenServiceTest, MultipleRequestsForTheSameScopesWithOneDeleted) {
   request.reset();
 
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token", 3600));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -326,6 +333,7 @@ TEST_F(OAuth2TokenServiceTest, ClearedRefreshTokenFailsSubsequentRequests) {
       std::set<std::string>(), &consumer_));
   base::RunLoop().RunUntilIdle();
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token", 3600));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -337,7 +345,7 @@ TEST_F(OAuth2TokenServiceTest, ClearedRefreshTokenFailsSubsequentRequests) {
   oauth2_service_->set_refresh_token("");
   request = oauth2_service_->StartRequest(std::set<std::string>(), &consumer_);
   base::RunLoop().RunUntilIdle();
-  EXPECT_EQ(fetcher, factory_.GetFetcherByID(0));
+  EXPECT_EQ(1U, factory_.GetFetcherCount());
   EXPECT_EQ(1, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(1, consumer_.number_of_errors_);
 }
@@ -352,7 +360,9 @@ TEST_F(OAuth2TokenServiceTest,
   scoped_ptr<OAuth2TokenService::Request> request(oauth2_service_->StartRequest(
       scopes, &consumer_));
   base::RunLoop().RunUntilIdle();
+  ASSERT_EQ(1U, factory_.GetFetcherCount());
   net::TestURLFetcher* fetcher1 = factory_.GetFetcherByID(0);
+  ASSERT_TRUE(fetcher1);
 
   // Note |request| is still pending when the refresh token changes.
   oauth2_service_->set_refresh_token("second refreshToken");
@@ -364,7 +374,8 @@ TEST_F(OAuth2TokenServiceTest,
       oauth2_service_->StartRequest(scopes, &consumer2));
   base::RunLoop().RunUntilIdle();
 
-  net::TestURLFetcher* fetcher2 = factory_.GetFetcherByID(0);
+  ASSERT_EQ(2U, factory_.GetFetcherCount());
+  net::TestURLFetcher* fetcher2 = factory_.GetFetcherByID(1);
   fetcher2->set_response_code(net::HTTP_OK);
   fetcher2->SetResponseString(GetValidTokenResponse("second token", 3600));
   fetcher2->delegate()->OnURLFetchComplete(fetcher2);
@@ -412,7 +423,8 @@ TEST_F(OAuth2TokenServiceTest, RetryingConsumer) {
   EXPECT_EQ(0, consumer.number_of_successful_tokens_);
   EXPECT_EQ(1, consumer.number_of_errors_);
 
-  fetcher = factory_.GetFetcherByID(0);
+  ASSERT_EQ(2U, factory_.GetFetcherCount());
+  fetcher = factory_.GetFetcherByID(1);
   ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
   fetcher->SetResponseString(std::string());
@@ -433,7 +445,7 @@ TEST_F(OAuth2TokenServiceTest, InvalidateToken) {
   EXPECT_EQ(0, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token", 3600));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -448,7 +460,7 @@ TEST_F(OAuth2TokenServiceTest, InvalidateToken) {
   base::RunLoop().RunUntilIdle();
 
   // No new network fetcher.
-  EXPECT_EQ(fetcher, factory_.GetFetcherByID(0));
+  ASSERT_EQ(1U, factory_.GetFetcherCount());
   EXPECT_EQ(2, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
   EXPECT_EQ("token", consumer_.last_token_);
@@ -460,8 +472,9 @@ TEST_F(OAuth2TokenServiceTest, InvalidateToken) {
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(2, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(0, consumer_.number_of_errors_);
-  fetcher = factory_.GetFetcherByID(0);
-  EXPECT_TRUE(fetcher);
+  ASSERT_EQ(2U, factory_.GetFetcherCount());
+  fetcher = factory_.GetFetcherByID(1);
+  ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_OK);
   fetcher->SetResponseString(GetValidTokenResponse("token2", 3600));
   fetcher->delegate()->OnURLFetchComplete(fetcher);
@@ -520,3 +533,105 @@ TEST_F(OAuth2TokenServiceTest, CancelRequestsForToken) {
   EXPECT_EQ(0, consumer_.number_of_successful_tokens_);
   EXPECT_EQ(3, consumer_.number_of_errors_);
 }
+
+TEST_F(OAuth2TokenServiceTest, SameScopesRequestedForDifferentClients) {
+  std::string client_id_1("client1");
+  std::string client_secret_1("secret1");
+  std::string client_id_2("client2");
+  std::string client_secret_2("secret2");
+  std::set<std::string> scope_set;
+  scope_set.insert("scope1");
+  scope_set.insert("scope2");
+
+  std::string refresh_token("refreshToken");
+  oauth2_service_->set_refresh_token(refresh_token);
+
+  scoped_ptr<OAuth2TokenService::Request> request1(
+      oauth2_service_->StartRequestForClient(client_id_1,
+                                             client_secret_1,
+                                             scope_set,
+                                             &consumer_));
+  scoped_ptr<OAuth2TokenService::Request> request2(
+      oauth2_service_->StartRequestForClient(client_id_2,
+                                             client_secret_2,
+                                             scope_set,
+                                             &consumer_));
+  // Start a request that should be duplicate of |request1|.
+  scoped_ptr<OAuth2TokenService::Request> request3(
+      oauth2_service_->StartRequestForClient(client_id_1,
+                                             client_secret_1,
+                                             scope_set,
+                                             &consumer_));
+  base::RunLoop().RunUntilIdle();
+
+  ASSERT_EQ(2U,
+            oauth2_service_->GetNumPendingRequestsForTesting(
+                client_id_1,
+                refresh_token,
+                scope_set));
+   ASSERT_EQ(1U,
+             oauth2_service_->GetNumPendingRequestsForTesting(
+                client_id_2,
+                refresh_token,
+                scope_set));
+}
+
+TEST_F(OAuth2TokenServiceTest, ClientScopeSetOrderTest) {
+  OAuth2TokenService::ScopeSet set_0;
+  OAuth2TokenService::ScopeSet set_1;
+  set_1.insert("1");
+
+  OAuth2TokenService::ClientScopeSet sets[] = {
+      OAuth2TokenService::ClientScopeSet("0", set_0),
+      OAuth2TokenService::ClientScopeSet("0", set_1),
+      OAuth2TokenService::ClientScopeSet("1", set_0),
+      OAuth2TokenService::ClientScopeSet("1", set_1),
+  };
+
+  for (size_t i = 0; i < arraysize(sets); i++) {
+    for (size_t j = 0; j < arraysize(sets); j++) {
+      if (i == j) {
+        EXPECT_FALSE(sets[i] < sets[j]) << " i=" << i << ", j=" << j;
+        EXPECT_FALSE(sets[j] < sets[i]) << " i=" << i << ", j=" << j;
+      } else if (i < j) {
+        EXPECT_TRUE(sets[i] < sets[j]) << " i=" << i << ", j=" << j;
+        EXPECT_FALSE(sets[j] < sets[i]) << " i=" << i << ", j=" << j;
+      } else {
+        EXPECT_TRUE(sets[j] < sets[i]) << " i=" << i << ", j=" << j;
+        EXPECT_FALSE(sets[i] < sets[j]) << " i=" << i << ", j=" << j;
+      }
+    }
+  }
+}
+
+TEST_F(OAuth2TokenServiceTest, FetchParametersOrderTest) {
+  OAuth2TokenService::ScopeSet set_0;
+  OAuth2TokenService::ScopeSet set_1;
+  set_1.insert("1");
+
+  OAuth2TokenService::FetchParameters params[] = {
+      OAuth2TokenService::FetchParameters("0", "0", set_0),
+      OAuth2TokenService::FetchParameters("0", "0", set_1),
+      OAuth2TokenService::FetchParameters("0", "1", set_0),
+      OAuth2TokenService::FetchParameters("0", "1", set_1),
+      OAuth2TokenService::FetchParameters("1", "0", set_0),
+      OAuth2TokenService::FetchParameters("1", "0", set_1),
+      OAuth2TokenService::FetchParameters("1", "1", set_0),
+      OAuth2TokenService::FetchParameters("1", "1", set_1),
+  };
+
+  for (size_t i = 0; i < arraysize(params); i++) {
+    for (size_t j = 0; j < arraysize(params); j++) {
+      if (i == j) {
+        EXPECT_FALSE(params[i] < params[j]) << " i=" << i << ", j=" << j;
+        EXPECT_FALSE(params[j] < params[i]) << " i=" << i << ", j=" << j;
+      } else if (i < j) {
+        EXPECT_TRUE(params[i] < params[j]) << " i=" << i << ", j=" << j;
+        EXPECT_FALSE(params[j] < params[i]) << " i=" << i << ", j=" << j;
+      } else {
+        EXPECT_TRUE(params[j] < params[i]) << " i=" << i << ", j=" << j;
+        EXPECT_FALSE(params[i] < params[j]) << " i=" << i << ", j=" << j;
+      }
+    }
+  }
+}