[Sync] Move sessions files from sync_driver to sync_sessions.

components/sync_driver.gypi

Index: components/sync_driver.gypi
diff --git a/components/sync_driver.gypi b/components/sync_driver.gypi
index 9df6a1810c509a2577acf5e4795e8f34feee618b..ed17165c1e856181b0ccd92dfc75a78cc8c141f7 100644
--- a/components/sync_driver.gypi
+++ b/components/sync_driver.gypi
@@ -77,9 +77,6 @@
         'sync_driver/glue/sync_backend_host_impl.h',
         'sync_driver/glue/sync_backend_registrar.cc',
         'sync_driver/glue/sync_backend_registrar.h',
-        'sync_driver/glue/synced_session.cc',
-        'sync_driver/glue/synced_session.h',
-        'sync_driver/glue/synced_window_delegate.h',
         'sync_driver/glue/ui_model_worker.cc',
         'sync_driver/glue/ui_model_worker.h',
         'sync_driver/invalidation_adapter.cc',
@@ -98,8 +95,6 @@
         'sync_driver/non_frontend_data_type_controller.h',
         'sync_driver/non_ui_data_type_controller.cc',
         'sync_driver/non_ui_data_type_controller.h',
-        'sync_driver/open_tabs_ui_delegate.cc',
-        'sync_driver/open_tabs_ui_delegate.h',
         'sync_driver/pref_names.cc',
         'sync_driver/pref_names.h',
         'sync_driver/profile_sync_auth_provider.cc',
@@ -108,8 +103,6 @@
         'sync_driver/protocol_event_observer.h',
         'sync_driver/proxy_data_type_controller.cc',
         'sync_driver/proxy_data_type_controller.h',
-        'sync_driver/sessions/synced_window_delegates_getter.cc',
-        'sync_driver/sessions/synced_window_delegates_getter.h',
         'sync_driver/shared_change_processor.cc',
         'sync_driver/shared_change_processor.h',
         'sync_driver/shared_change_processor_ref.cc',
@@ -142,22 +135,11 @@
         'sync_driver/sync_util.h',
         'sync_driver/system_encryptor.cc',
         'sync_driver/system_encryptor.h',
-        'sync_driver/tab_node_pool.cc',
-        'sync_driver/tab_node_pool.h',
         'sync_driver/ui_data_type_controller.cc',
         'sync_driver/ui_data_type_controller.h',
         'sync_driver/user_selectable_sync_type.h',
       ],
       'conditions': [
-        ['OS!="ios"', {
-          'dependencies': [
-            'sessions_content',
-          ],
-        }, {  # OS==ios
-          'dependencies': [
-            'sessions_ios',
-          ],
-        }],
         ['configuration_policy==1', {
           'dependencies': [
             'policy',