Add request throttler to thumbnail fetching for articles on mobile NTP

components/ntp_snippets/pref_names.cc

Index: components/ntp_snippets/pref_names.cc
diff --git a/components/ntp_snippets/pref_names.cc b/components/ntp_snippets/pref_names.cc
index 67e1dc64b30b246b755e1ff51c69b073b0eddaa2..0ef1c793ea639ad80d309049f6de31be07bcea99 100644
--- a/components/ntp_snippets/pref_names.cc
+++ b/components/ntp_snippets/pref_names.cc
@@ -11,10 +11,19 @@ const char kEnableSnippets[] = "ntp_snippets.enable";
 
 const char kSnippetHosts[] = "ntp_snippets.hosts";
 
-const char kSnippetFetcherQuotaDay[] =
-    "ntp.request_throttler.suggestion_fetcher.day";
-const char kSnippetFetcherQuotaCount[] =
+const char kSnippetFetcherRequestCount[] =
     "ntp.request_throttler.suggestion_fetcher.count";
+const char kSnippetFetcherInteractiveRequestCount[] =
+    "ntp.request_throttler.suggestion_fetcher.interactive_count";
+const char kSnippetFetcherRequestsDay[] =
+    "ntp.request_throttler.suggestion_fetcher.day";
+
+const char kSnippetThumbnailsRequestCount[] =
+    "ntp.request_throttler.suggestion_thumbnails.count";
+const char kSnippetThumbnailsInteractiveRequestCount[] =
+    "ntp.request_throttler.suggestion_thumbnails.interactive_count";
+const char kSnippetThumbnailsRequestsDay[] =
+    "ntp.request_throttler.suggestion_thumbnails.day";
 
 }  // namespace prefs
 }  // namespace ntp_snippets