[Sync] Remove calls to MakeUserAgentForSyncApi.

BUG=512036

Review URL: https://codereview.chromium.org/1258563009

Cr-Commit-Position: refs/heads/master@{#342842}

19 files changed, 73 insertions, 48 deletions

diff --git a/chrome/browser/sync/glue/local_device_info_provider_impl.cc b/chrome/browser/sync/glue/local_device_info_provider_impl.cc
index 9a59c4c..329cbaa 100644
--- a/chrome/browser/sync/glue/local_device_info_provider_impl.cc
+++ b/chrome/browser/sync/glue/local_device_info_provider_impl.cc
@@ -46,25 +46,25 @@ LocalDeviceInfoProviderImpl::LocalDeviceInfoProviderImpl()
 LocalDeviceInfoProviderImpl::~LocalDeviceInfoProviderImpl() {
 }
 
-// static.
-std::string LocalDeviceInfoProviderImpl::MakeUserAgentForSyncApi() {
+const sync_driver::DeviceInfo*
+LocalDeviceInfoProviderImpl::GetLocalDeviceInfo() const {
+  return local_device_info_.get();
+}
+
+std::string LocalDeviceInfoProviderImpl::GetSyncUserAgent() const {
 #if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
   return MakeDesktopUserAgentForSync();
 #elif defined(OS_CHROMEOS)
   return MakeUserAgentForSync("CROS ");
 #elif defined(OS_ANDROID)
-  if (IsTabletUI())
+  if (IsTabletUI()) {
     return MakeUserAgentForSync("ANDROID-TABLET ");
-  else
+  } else {
     return MakeUserAgentForSync("ANDROID-PHONE ");
+  }
 #endif
 }
 
-const sync_driver::DeviceInfo*
-LocalDeviceInfoProviderImpl::GetLocalDeviceInfo() const {
-  return local_device_info_.get();
-}
-
 std::string LocalDeviceInfoProviderImpl::GetLocalSyncCacheGUID() const {
   return cache_guid_;
 }
@@ -97,7 +97,7 @@ void LocalDeviceInfoProviderImpl::InitializeContinuation(
       new sync_driver::DeviceInfo(guid,
                                   session_name,
                                   chrome::GetVersionString(),
-                                  MakeUserAgentForSyncApi(),
+                                  GetSyncUserAgent(),
                                   GetLocalDeviceType(),
                                   signin_scoped_device_id));
 
diff --git a/chrome/browser/sync/glue/local_device_info_provider_impl.h b/chrome/browser/sync/glue/local_device_info_provider_impl.h
index 7764c95..7323cf2 100644
--- a/chrome/browser/sync/glue/local_device_info_provider_impl.h
+++ b/chrome/browser/sync/glue/local_device_info_provider_impl.h
@@ -19,18 +19,15 @@ class LocalDeviceInfoProviderImpl
 
   // LocalDeviceInfoProvider implementation.
   const sync_driver::DeviceInfo* GetLocalDeviceInfo() const override;
+  std::string GetSyncUserAgent() const override;
   std::string GetLocalSyncCacheGUID() const override;
   void Initialize(const std::string& cache_guid,
                   const std::string& signin_scoped_device_id) override;
   scoped_ptr<Subscription> RegisterOnInitializedCallback(
       const base::Closure& callback) override;
 
-  // Helper to construct a user agent string (ASCII) suitable for use by
-  // the syncapi for any HTTP communication. This string is used by the sync
-  // backend for classifying client types when calculating statistics.
-  static std::string MakeUserAgentForSyncApi();
-
  private:
+
   void InitializeContinuation(const std::string& guid,
                               const std::string& signin_scoped_device_id,
                               const std::string& session_name);
diff --git a/chrome/browser/sync/glue/local_device_info_provider_unittest.cc b/chrome/browser/sync/glue/local_device_info_provider_unittest.cc
index 66afcf4..9176c30 100644
--- a/chrome/browser/sync/glue/local_device_info_provider_unittest.cc
+++ b/chrome/browser/sync/glue/local_device_info_provider_unittest.cc
@@ -78,9 +78,8 @@ TEST_F(LocalDeviceInfoProviderTest, GetLocalDeviceInfo) {
   EXPECT_EQ(syncer::GetSessionNameSynchronouslyForTesting(),
             local_device_info->client_name());
 
-  EXPECT_EQ(
-      browser_sync::LocalDeviceInfoProviderImpl::MakeUserAgentForSyncApi(),
-      local_device_info->sync_user_agent());
+  EXPECT_EQ(provider_->GetSyncUserAgent(),
+            local_device_info->sync_user_agent());
 }
 
 TEST_F(LocalDeviceInfoProviderTest, GetLocalSyncCacheGUID) {
diff --git a/chrome/browser/sync/glue/sync_backend_host.h b/chrome/browser/sync/glue/sync_backend_host.h
index 4ec057a..9ef864c 100644
--- a/chrome/browser/sync/glue/sync_backend_host.h
+++ b/chrome/browser/sync/glue/sync_backend_host.h
@@ -64,6 +64,7 @@ class SyncBackendHost : public sync_driver::BackendDataTypeConfigurer {
       scoped_ptr<base::Thread> sync_thread,
       const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
       const GURL& service_url,
+      const std::string& sync_user_agent,
       const syncer::SyncCredentials& credentials,
       bool delete_sync_data_folder,
       scoped_ptr<syncer::SyncManagerFactory> sync_manager_factory,
diff --git a/chrome/browser/sync/glue/sync_backend_host_core.cc b/chrome/browser/sync/glue/sync_backend_host_core.cc
index d08e1a5..621c54c 100644
--- a/chrome/browser/sync/glue/sync_backend_host_core.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_core.cc
@@ -61,6 +61,7 @@ DoInitializeOptions::DoInitializeOptions(
     const scoped_refptr<syncer::ExtensionsActivity>& extensions_activity,
     const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
     const GURL& service_url,
+    const std::string& sync_user_agent,
     scoped_ptr<syncer::HttpPostProviderFactory> http_bridge_factory,
     const syncer::SyncCredentials& credentials,
     const std::string& invalidator_client_id,
@@ -82,6 +83,7 @@ DoInitializeOptions::DoInitializeOptions(
       extensions_activity(extensions_activity),
       event_handler(event_handler),
       service_url(service_url),
+      sync_user_agent(sync_user_agent),
       http_bridge_factory(http_bridge_factory.Pass()),
       credentials(credentials),
       invalidator_client_id(invalidator_client_id),
@@ -423,8 +425,7 @@ void SyncBackendHostCore::DoInitialize(
 
   // Finish initializing the HttpBridgeFactory.  We do this here because
   // building the user agent may block on some platforms.
-  options->http_bridge_factory->Init(
-      LocalDeviceInfoProviderImpl::MakeUserAgentForSyncApi());
+  options->http_bridge_factory->Init(options->sync_user_agent);
 
   // Blow away the partial or corrupt sync data folder before doing any more
   // initialization, if necessary.
diff --git a/chrome/browser/sync/glue/sync_backend_host_core.h b/chrome/browser/sync/glue/sync_backend_host_core.h
index bcd0ea9..489f1af 100644
--- a/chrome/browser/sync/glue/sync_backend_host_core.h
+++ b/chrome/browser/sync/glue/sync_backend_host_core.h
@@ -31,6 +31,7 @@ struct DoInitializeOptions {
       const scoped_refptr<syncer::ExtensionsActivity>& extensions_activity,
       const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
       const GURL& service_url,
+      const std::string& sync_user_agent,
       scoped_ptr<syncer::HttpPostProviderFactory> http_bridge_factory,
       const syncer::SyncCredentials& credentials,
       const std::string& invalidator_client_id,
@@ -54,6 +55,7 @@ struct DoInitializeOptions {
   scoped_refptr<syncer::ExtensionsActivity> extensions_activity;
   syncer::WeakHandle<syncer::JsEventHandler> event_handler;
   GURL service_url;
+  std::string sync_user_agent;
   // Overridden by tests.
   scoped_ptr<syncer::HttpPostProviderFactory> http_bridge_factory;
   syncer::SyncCredentials credentials;
diff --git a/chrome/browser/sync/glue/sync_backend_host_impl.cc b/chrome/browser/sync/glue/sync_backend_host_impl.cc
index 598c0e1..d04ac0b 100644
--- a/chrome/browser/sync/glue/sync_backend_host_impl.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_impl.cc
@@ -102,6 +102,7 @@ void SyncBackendHostImpl::Initialize(
     scoped_ptr<base::Thread> sync_thread,
     const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
     const GURL& sync_service_url,
+    const std::string& sync_user_agent,
     const syncer::SyncCredentials& credentials,
     bool delete_sync_data_folder,
     scoped_ptr<syncer::SyncManagerFactory> sync_manager_factory,
@@ -148,7 +149,7 @@ void SyncBackendHostImpl::Initialize(
   scoped_ptr<DoInitializeOptions> init_opts(new DoInitializeOptions(
       registrar_->sync_thread()->message_loop(), registrar_.get(), routing_info,
       workers, extensions_activity_monitor_.GetExtensionsActivity(),
-      event_handler, sync_service_url,
+      event_handler, sync_service_url, sync_user_agent,
       network_resources->GetHttpPostProviderFactory(
           make_scoped_refptr(profile_->GetRequestContext()),
           base::Bind(&UpdateNetworkTime),
diff --git a/chrome/browser/sync/glue/sync_backend_host_impl.h b/chrome/browser/sync/glue/sync_backend_host_impl.h
index 3f15018..21b7acb 100644
--- a/chrome/browser/sync/glue/sync_backend_host_impl.h
+++ b/chrome/browser/sync/glue/sync_backend_host_impl.h
@@ -83,6 +83,7 @@ class SyncBackendHostImpl
       scoped_ptr<base::Thread> sync_thread,
       const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
       const GURL& service_url,
+      const std::string& sync_user_agent,
       const syncer::SyncCredentials& credentials,
       bool delete_sync_data_folder,
       scoped_ptr<syncer::SyncManagerFactory> sync_manager_factory,
diff --git a/chrome/browser/sync/glue/sync_backend_host_impl_unittest.cc b/chrome/browser/sync/glue/sync_backend_host_impl_unittest.cc
index 9539b9c..3723793 100644
--- a/chrome/browser/sync/glue/sync_backend_host_impl_unittest.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_impl_unittest.cc
@@ -215,6 +215,7 @@ class SyncBackendHostTest : public testing::Test {
         scoped_ptr<base::Thread>(),
         syncer::WeakHandle<syncer::JsEventHandler>(),
         GURL(std::string()),
+        std::string(),
         credentials_,
         true,
         fake_manager_factory_.Pass(),
diff --git a/chrome/browser/sync/glue/sync_backend_host_mock.cc b/chrome/browser/sync/glue/sync_backend_host_mock.cc
index d63f7c4..a6deee1 100644
--- a/chrome/browser/sync/glue/sync_backend_host_mock.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_mock.cc
@@ -18,6 +18,7 @@ void SyncBackendHostMock::Initialize(
     scoped_ptr<base::Thread> sync_thread,
     const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
     const GURL& service_url,
+    const std::string& sync_user_agent,
     const syncer::SyncCredentials& credentials,
     bool delete_sync_data_folder,
     scoped_ptr<syncer::SyncManagerFactory> sync_manager_factory,
diff --git a/chrome/browser/sync/glue/sync_backend_host_mock.h b/chrome/browser/sync/glue/sync_backend_host_mock.h
index 6ec17e9..fab5d91 100644
--- a/chrome/browser/sync/glue/sync_backend_host_mock.h
+++ b/chrome/browser/sync/glue/sync_backend_host_mock.h
@@ -30,6 +30,7 @@ class SyncBackendHostMock : public SyncBackendHost {
       scoped_ptr<base::Thread> sync_thread,
       const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
       const GURL& service_url,
+      const std::string& sync_user_agent,
       const syncer::SyncCredentials& credentials,
       bool delete_sync_data_folder,
       scoped_ptr<syncer::SyncManagerFactory> sync_manager_factory,
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index 453252b..b144dfb 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -238,11 +238,6 @@ ProfileSyncService::ProfileSyncService(
       backup_finished_(false),
       clear_browsing_data_(base::Bind(&ClearBrowsingData)),
       browsing_data_remover_observer_(NULL),
-      sync_stopped_reporter_(
-          new browser_sync::SyncStoppedReporter(
-              sync_service_url_,
-              profile_->GetRequestContext(),
-              browser_sync::SyncStoppedReporter::ResultCallback())),
       weak_factory_(this),
       startup_controller_weak_factory_(this) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
@@ -271,6 +266,12 @@ ProfileSyncService::ProfileSyncService(
 
   DCHECK(factory_.get());
   local_device_ = factory_->CreateLocalDeviceInfoProvider();
+  sync_stopped_reporter_.reset(
+          new browser_sync::SyncStoppedReporter(
+              sync_service_url_,
+              local_device_->GetSyncUserAgent(),
+              profile_->GetRequestContext(),
+              browser_sync::SyncStoppedReporter::ResultCallback())),
   sessions_sync_manager_.reset(
       new SessionsSyncManager(profile, local_device_.get(), router.Pass()));
   device_info_sync_service_.reset(
@@ -526,7 +527,9 @@ void ProfileSyncService::InitializeBackend(bool delete_stale_data) {
     ClearStaleErrors();
 
   backend_->Initialize(this, sync_thread_.Pass(), GetJsEventHandler(),
-                       sync_service_url_, credentials, delete_stale_data,
+                       sync_service_url_,
+                       local_device_->GetSyncUserAgent(),
+                       credentials, delete_stale_data,
                        scoped_ptr<syncer::SyncManagerFactory>(
                            new syncer::SyncManagerFactory(GetManagerType()))
                            .Pass(),
diff --git a/chrome/browser/sync/profile_sync_service_unittest.cc b/chrome/browser/sync/profile_sync_service_unittest.cc
index 0d58a79..4570cc8 100644
--- a/chrome/browser/sync/profile_sync_service_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_unittest.cc
@@ -112,6 +112,7 @@ class SyncBackendHostNoReturn : public SyncBackendHostMock {
       scoped_ptr<base::Thread> sync_thread,
       const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
       const GURL& service_url,
+      const std::string& sync_user_agent,
       const syncer::SyncCredentials& credentials,
       bool delete_sync_data_folder,
       scoped_ptr<syncer::SyncManagerFactory> sync_manager_factory,
@@ -134,6 +135,7 @@ class SyncBackendHostMockCollectDeleteDirParam : public SyncBackendHostMock {
       scoped_ptr<base::Thread> sync_thread,
       const syncer::WeakHandle<syncer::JsEventHandler>& event_handler,
       const GURL& service_url,
+      const std::string& sync_user_agent,
       const syncer::SyncCredentials& credentials,
       bool delete_sync_data_folder,
       scoped_ptr<syncer::SyncManagerFactory> sync_manager_factory,
@@ -145,8 +147,8 @@ class SyncBackendHostMockCollectDeleteDirParam : public SyncBackendHostMock {
       override {
     delete_dir_param_->push_back(delete_sync_data_folder);
     SyncBackendHostMock::Initialize(frontend, sync_thread.Pass(),
-                                    event_handler, service_url, credentials,
-                                    delete_sync_data_folder,
+                                    event_handler, service_url, sync_user_agent,
+                                    credentials, delete_sync_data_folder,
                                     sync_manager_factory.Pass(),
                                     unrecoverable_error_handler,
                                     report_unrecoverable_error_function,
diff --git a/chrome/browser/sync/sync_stopped_reporter.cc b/chrome/browser/sync/sync_stopped_reporter.cc
index b0145f5..22fcd09 100644
--- a/chrome/browser/sync/sync_stopped_reporter.cc
+++ b/chrome/browser/sync/sync_stopped_reporter.cc
@@ -28,20 +28,17 @@ const char kEventEndpoint[] = "event";
 // perspective either. This seems like a good compromise.
 const int kRequestTimeoutSeconds = 10;
 
-std::string GetUserAgent() {
-  return browser_sync::LocalDeviceInfoProviderImpl::MakeUserAgentForSyncApi();
-}
-
 }  // namespace
 
 namespace browser_sync {
 
 SyncStoppedReporter::SyncStoppedReporter(
     const GURL& sync_service_url,
+    const std::string& user_agent,
     const scoped_refptr<net::URLRequestContextGetter>& request_context,
     const ResultCallback& callback)
     : sync_event_url_(GetSyncEventURL(sync_service_url)),
-      user_agent_(GetUserAgent()),
+      user_agent_(user_agent),
       request_context_(request_context),
       callback_(callback) {
   DCHECK(!sync_service_url.is_empty());
diff --git a/chrome/browser/sync/sync_stopped_reporter.h b/chrome/browser/sync/sync_stopped_reporter.h
index a2575ec..fd5eb2ee 100644
--- a/chrome/browser/sync/sync_stopped_reporter.h
+++ b/chrome/browser/sync/sync_stopped_reporter.h
@@ -29,6 +29,7 @@ class SyncStoppedReporter : public net::URLFetcherDelegate {
   typedef base::Callback<void(const Result&)> ResultCallback;
 
   SyncStoppedReporter(const GURL& sync_service_url,
+      const std::string& user_agent,
       const scoped_refptr<net::URLRequestContextGetter>& request_context,
       const ResultCallback& callback);
   ~SyncStoppedReporter() override;
diff --git a/chrome/browser/sync/sync_stopped_reporter_unittest.cc b/chrome/browser/sync/sync_stopped_reporter_unittest.cc
index eab9f14..d8bd6e4 100644
--- a/chrome/browser/sync/sync_stopped_reporter_unittest.cc
+++ b/chrome/browser/sync/sync_stopped_reporter_unittest.cc
@@ -22,6 +22,7 @@ const char kTestURL[] = "http://chromium.org/test";
 const char kTestURLTrailingSlash[] = "http://chromium.org/test/";
 const char kEventURL[] = "http://chromium.org/test/event";
 
+const char kTestUserAgent[] = "the_fifth_element";
 const char kAuthToken[] = "multipass";
 const char kCacheGuid[] = "leeloo";
 const char kBirthday[] = "2263";
@@ -46,6 +47,10 @@ class SyncStoppedReporterTest : public testing::Test {
     return GURL(kTestURL);
   }
 
+  std::string user_agent() const {
+    return std::string(kTestUserAgent);
+  }
+
   SyncStoppedReporter::ResultCallback callback() {
     return base::Bind(&SyncStoppedReporterTest::RequestFinishedCallback,
                       base::Unretained(this));
@@ -59,10 +64,6 @@ class SyncStoppedReporterTest : public testing::Test {
     return request_context_.get();
   }
 
-  static std::string GetUserAgent() {
-    return browser_sync::LocalDeviceInfoProviderImpl::MakeUserAgentForSyncApi();
-  }
-
  private:
   base::MessageLoop message_loop_;
   scoped_refptr<net::URLRequestContextGetter> request_context_;
@@ -74,7 +75,8 @@ class SyncStoppedReporterTest : public testing::Test {
 // Test that the event URL gets constructed correctly.
 TEST_F(SyncStoppedReporterTest, EventURL) {
   net::TestURLFetcherFactory factory;
-  SyncStoppedReporter ssr(GURL(kTestURL), request_context(), callback());
+  SyncStoppedReporter ssr(GURL(kTestURL), user_agent(),
+                          request_context(), callback());
   ssr.ReportSyncStopped(kAuthToken, kCacheGuid, kBirthday);
   net::TestURLFetcher* fetcher = factory.GetFetcherByID(0);
   EXPECT_EQ(kEventURL, fetcher->GetOriginalURL().spec());
@@ -83,7 +85,7 @@ TEST_F(SyncStoppedReporterTest, EventURL) {
 // Test that the event URL gets constructed correctly with a trailing slash.
 TEST_F(SyncStoppedReporterTest, EventURLWithSlash) {
   net::TestURLFetcherFactory factory;
-  SyncStoppedReporter ssr(GURL(kTestURLTrailingSlash),
+  SyncStoppedReporter ssr(GURL(kTestURLTrailingSlash), user_agent(),
                           request_context(), callback());
   ssr.ReportSyncStopped(kAuthToken, kCacheGuid, kBirthday);
   net::TestURLFetcher* fetcher = factory.GetFetcherByID(0);
@@ -93,7 +95,8 @@ TEST_F(SyncStoppedReporterTest, EventURLWithSlash) {
 // Test that the URLFetcher gets configured correctly.
 TEST_F(SyncStoppedReporterTest, FetcherConfiguration) {
   net::TestURLFetcherFactory factory;
-  SyncStoppedReporter ssr(test_url(), request_context(), callback());
+  SyncStoppedReporter ssr(test_url(), user_agent(),
+                          request_context(), callback());
   ssr.ReportSyncStopped(kAuthToken, kCacheGuid, kBirthday);
   net::TestURLFetcher* fetcher = factory.GetFetcherByID(0);
 
@@ -106,7 +109,7 @@ TEST_F(SyncStoppedReporterTest, FetcherConfiguration) {
   auth_header.append(kAuthToken);
   EXPECT_EQ(auth_header, header);
   headers.GetHeader(net::HttpRequestHeaders::kUserAgent, &header);
-  EXPECT_EQ(GetUserAgent(), header);
+  EXPECT_EQ(user_agent(), header);
 
   sync_pb::EventRequest event_request;
   event_request.ParseFromString(fetcher->upload_data());
@@ -118,7 +121,8 @@ TEST_F(SyncStoppedReporterTest, FetcherConfiguration) {
 
 TEST_F(SyncStoppedReporterTest, HappyCase) {
   net::TestURLFetcherFactory factory;
-  SyncStoppedReporter ssr(test_url(), request_context(), callback());
+  SyncStoppedReporter ssr(test_url(), user_agent(),
+                          request_context(), callback());
   ssr.ReportSyncStopped(kAuthToken, kCacheGuid, kBirthday);
   net::TestURLFetcher* fetcher = factory.GetFetcherByID(0);
   fetcher->set_response_code(net::HTTP_OK);
@@ -130,7 +134,8 @@ TEST_F(SyncStoppedReporterTest, HappyCase) {
 
 TEST_F(SyncStoppedReporterTest, ServerNotFound) {
   net::TestURLFetcherFactory factory;
-  SyncStoppedReporter ssr(test_url(), request_context(), callback());
+  SyncStoppedReporter ssr(test_url(), user_agent(),
+                          request_context(), callback());
   ssr.ReportSyncStopped(kAuthToken, kCacheGuid, kBirthday);
   net::TestURLFetcher* fetcher = factory.GetFetcherByID(0);
   fetcher->set_response_code(net::HTTP_NOT_FOUND);
@@ -144,7 +149,8 @@ TEST_F(SyncStoppedReporterTest, DestructionDuringRequestHandler) {
   net::TestURLFetcherFactory factory;
   factory.set_remove_fetcher_on_delete(true);
   {
-    SyncStoppedReporter ssr(test_url(), request_context(), callback());
+    SyncStoppedReporter ssr(test_url(), user_agent(),
+                            request_context(), callback());
     ssr.ReportSyncStopped(kAuthToken, kCacheGuid, kBirthday);
     EXPECT_FALSE(factory.GetFetcherByID(0) == nullptr);
   }
@@ -152,7 +158,8 @@ TEST_F(SyncStoppedReporterTest, DestructionDuringRequestHandler) {
 }
 
 TEST_F(SyncStoppedReporterTest, Timeout) {
-  SyncStoppedReporter ssr(test_url(), request_context(), callback());
+  SyncStoppedReporter ssr(test_url(), user_agent(),
+                          request_context(), callback());
 
   // A task runner that can trigger the timeout immediately.
   scoped_refptr<base::TestSimpleTaskRunner> task_runner(
@@ -173,7 +180,7 @@ TEST_F(SyncStoppedReporterTest, Timeout) {
 
 TEST_F(SyncStoppedReporterTest, NoCallback) {
   net::TestURLFetcherFactory factory;
-  SyncStoppedReporter ssr(GURL(kTestURL), request_context(),
+  SyncStoppedReporter ssr(GURL(kTestURL), user_agent(), request_context(),
                           SyncStoppedReporter::ResultCallback());
   ssr.ReportSyncStopped(kAuthToken, kCacheGuid, kBirthday);
   net::TestURLFetcher* fetcher = factory.GetFetcherByID(0);
@@ -182,7 +189,7 @@ TEST_F(SyncStoppedReporterTest, NoCallback) {
 }
 
 TEST_F(SyncStoppedReporterTest, NoCallbackTimeout) {
-  SyncStoppedReporter ssr(GURL(kTestURL), request_context(),
+  SyncStoppedReporter ssr(GURL(kTestURL), user_agent(), request_context(),
                           SyncStoppedReporter::ResultCallback());
 
   // A task runner that can trigger the timeout immediately.
diff --git a/components/sync_driver/local_device_info_provider.h b/components/sync_driver/local_device_info_provider.h
index 6036a7e..d61041e 100644
--- a/components/sync_driver/local_device_info_provider.h
+++ b/components/sync_driver/local_device_info_provider.h
@@ -27,6 +27,11 @@ class LocalDeviceInfoProvider {
   // is destroyed.
   virtual const DeviceInfo* GetLocalDeviceInfo() const = 0;
 
+  // Constructs a user agent string (ASCII) suitable for use by the syncapi
+  // for any HTTP communication. This string is used by the sync backend for
+  // classifying client types when calculating statistics.
+  virtual std::string GetSyncUserAgent() const = 0;
+
   // Returns a GUID string used for creation of the machine tag for
   // this local session; an empty sting if LocalDeviceInfoProvider hasn't been
   // initialized yet.
diff --git a/components/sync_driver/local_device_info_provider_mock.cc b/components/sync_driver/local_device_info_provider_mock.cc
index 2acf49d..644c1b1 100644
--- a/components/sync_driver/local_device_info_provider_mock.cc
+++ b/components/sync_driver/local_device_info_provider_mock.cc
@@ -33,6 +33,10 @@ const DeviceInfo* LocalDeviceInfoProviderMock::GetLocalDeviceInfo() const {
   return is_initialized_ ? local_device_info_.get() : NULL;
 }
 
+std::string LocalDeviceInfoProviderMock::GetSyncUserAgent() const {
+  return "useragent";
+}
+
 std::string LocalDeviceInfoProviderMock::GetLocalSyncCacheGUID() const {
   return local_device_info_.get() ? local_device_info_->guid() : "";
 }
diff --git a/components/sync_driver/local_device_info_provider_mock.h b/components/sync_driver/local_device_info_provider_mock.h
index 60c6a45..5cea163 100644
--- a/components/sync_driver/local_device_info_provider_mock.h
+++ b/components/sync_driver/local_device_info_provider_mock.h
@@ -26,6 +26,7 @@ class LocalDeviceInfoProviderMock
   ~LocalDeviceInfoProviderMock() override;
 
   const DeviceInfo* GetLocalDeviceInfo() const override;
+  std::string GetSyncUserAgent() const override;
   std::string GetLocalSyncCacheGUID() const override;
   void Initialize(const std::string& cache_guid,
                   const std::string& signin_scoped_device_id) override;