[NTP Snippets] Refactor background scheduling for remote suggestions

components/ntp_snippets/BUILD.gn

Index: components/ntp_snippets/BUILD.gn
diff --git a/components/ntp_snippets/BUILD.gn b/components/ntp_snippets/BUILD.gn
index 8d68dfb31dbac2ef2e0f015414d0a4ac13c01839..7268b94ad1282e47a8ca16b891ed2ba93656f427 100644
--- a/components/ntp_snippets/BUILD.gn
+++ b/components/ntp_snippets/BUILD.gn
@@ -48,7 +48,7 @@ static_library("ntp_snippets") {
     "remote/ntp_snippet.h",
     "remote/ntp_snippets_fetcher.cc",
     "remote/ntp_snippets_fetcher.h",
-    "remote/ntp_snippets_scheduler.h",
+    "remote/persistent_scheduler.h",
     "remote/remote_suggestions_database.cc",
     "remote/remote_suggestions_database.h",
     "remote/remote_suggestions_provider.cc",
@@ -57,6 +57,8 @@ static_library("ntp_snippets") {
     "remote/remote_suggestions_status_service.h",
     "remote/request_throttler.cc",
     "remote/request_throttler.h",
+    "remote/scheduling_remote_suggestions_provider.cc",
+    "remote/scheduling_remote_suggestions_provider.h",
     "sessions/foreign_sessions_suggestions_provider.cc",
     "sessions/foreign_sessions_suggestions_provider.h",
     "sessions/tab_delegate_sync_adapter.cc",
@@ -124,6 +126,7 @@ source_set("unit_tests") {
     "remote/ntp_snippets_fetcher_unittest.cc",
     "remote/remote_suggestions_database_unittest.cc",
     "remote/remote_suggestions_provider_unittest.cc",
+    "remote/remote_suggestions_scheduler_unittest.cc",
     "remote/remote_suggestions_status_service_unittest.cc",
     "remote/request_throttler_unittest.cc",
     "remote/test_utils.cc",