[Sync] Creating sync_sessions component, moving revisit logic.

components/components_tests.gyp

Index: components/components_tests.gyp
diff --git a/components/components_tests.gyp b/components/components_tests.gyp
index 24df75ff86014cd2fd4177c1fc6533df5c98607e..9d3f54dca1de24a6d31f431f8868733c27631f0d 100644
--- a/components/components_tests.gyp
+++ b/components/components_tests.gyp
@@ -655,9 +655,6 @@
       'sync_driver/model_association_manager_unittest.cc',
       'sync_driver/non_blocking_data_type_controller_unittest.cc',
       'sync_driver/non_ui_data_type_controller_unittest.cc',
-      'sync_driver/revisit/current_tab_matcher_unittest.cc',
-      'sync_driver/revisit/offset_tab_matcher_unittest.cc',
-      'sync_driver/revisit/sessions_page_revisit_observer_unittest.cc',
       'sync_driver/shared_change_processor_unittest.cc',
       'sync_driver/sync_prefs_unittest.cc',
       'sync_driver/sync_stopped_reporter_unittest.cc',
@@ -666,6 +663,11 @@
       'sync_driver/tab_node_pool_unittest.cc',
       'sync_driver/ui_data_type_controller_unittest.cc',
     ],
+    'sync_sessions_unittest_sources': [
+      'sync_sessions/revisit/current_tab_matcher_unittest.cc',
+      'sync_sessions/revisit/offset_tab_matcher_unittest.cc',
+      'sync_sessions/revisit/sessions_page_revisit_observer_unittest.cc',
+    ],
     'syncable_prefs_unittest_sources': [
       'syncable_prefs/pref_model_associator_unittest.cc',
       'syncable_prefs/pref_service_syncable_unittest.cc',
@@ -861,6 +863,7 @@
         '<@(signin_unittest_sources)',
         '<@(suggestions_unittest_sources)',
         '<@(sync_driver_unittest_sources)',
+        '<@(sync_sessions_unittest_sources)',
         '<@(syncable_prefs_unittest_sources)',
         '<@(translate_unittest_sources)',
         '<@(undo_unittest_sources)',
@@ -982,6 +985,7 @@
         'components.gyp:signin_core_browser_test_support',
         'components.gyp:suggestions',
         'components.gyp:sync_driver_test_support',
+        'components.gyp:sync_sessions_test_support',
         'components.gyp:syncable_prefs_test_support',
         'components.gyp:translate_core_browser',
         'components.gyp:translate_core_common',