[Sync] Creating sync_sessions component, moving revisit logic.

components/sync_driver/BUILD.gn

Index: components/sync_driver/BUILD.gn
diff --git a/components/sync_driver/BUILD.gn b/components/sync_driver/BUILD.gn
index 340c766d107179af9c925efd126ac719d8a08e68..77f3c71f9d5a0091d99ce57e203b72a85e8ffe4f 100644
--- a/components/sync_driver/BUILD.gn
+++ b/components/sync_driver/BUILD.gn
@@ -83,14 +83,6 @@ source_set("sync_driver") {
     "protocol_event_observer.h",
     "proxy_data_type_controller.cc",
     "proxy_data_type_controller.h",
-    "revisit/current_tab_matcher.cc",
-    "revisit/current_tab_matcher.h",
-    "revisit/offset_tab_matcher.cc",
-    "revisit/offset_tab_matcher.h",
-    "revisit/page_equality.h",
-    "revisit/page_visit_observer.h",
-    "revisit/sessions_page_revisit_observer.cc",
-    "revisit/sessions_page_revisit_observer.h",
     "sessions/synced_window_delegates_getter.cc",
     "sessions/synced_window_delegates_getter.h",
     "shared_change_processor.cc",
@@ -214,9 +206,6 @@ source_set("unit_tests") {
     "model_association_manager_unittest.cc",
     "non_blocking_data_type_controller_unittest.cc",
     "non_ui_data_type_controller_unittest.cc",
-    "revisit/current_tab_matcher_unittest.cc",
-    "revisit/offset_tab_matcher_unittest.cc",
-    "revisit/sessions_page_revisit_observer_unittest.cc",
     "shared_change_processor_unittest.cc",
     "sync_prefs_unittest.cc",
     "sync_stopped_reporter_unittest.cc",