Skip enhanced bookmarks cluster requests if it's not being used.

chrome/browser/enhanced_bookmarks/chrome_bookmark_server_cluster_service.cc

Index: chrome/browser/enhanced_bookmarks/chrome_bookmark_server_cluster_service.cc
diff --git a/chrome/browser/enhanced_bookmarks/chrome_bookmark_server_cluster_service.cc b/chrome/browser/enhanced_bookmarks/chrome_bookmark_server_cluster_service.cc
index 8f1540deadcc474b0fe9f89a4bfa0c63d57720c8..498c0116060bc7d90738d051777c0396c4c88cc0 100644
--- a/chrome/browser/enhanced_bookmarks/chrome_bookmark_server_cluster_service.cc
+++ b/chrome/browser/enhanced_bookmarks/chrome_bookmark_server_cluster_service.cc
@@ -33,6 +33,15 @@ ChromeBookmarkServerClusterService::~ChromeBookmarkServerClusterService() {
     sync_service_->RemoveObserver(this);
 }
 
+void ChromeBookmarkServerClusterService::AddObserver(
+    BookmarkServerServiceObserver* observer) {
+  BookmarkServerClusterService::AddObserver(observer);
+  if (sync_refresh_skipped_) {
+    sync_refresh_skipped_ = false;
+    TriggerTokenRequest(false);
+  }
+}
+
 void ChromeBookmarkServerClusterService::OnStateChanged() {
   // Do nothing.
 }
@@ -42,10 +51,14 @@ void ChromeBookmarkServerClusterService::OnSyncCycleCompleted() {
   // cluster request immediately after a bookmark is changed from the bookmark
   // observer notification will yield the wrong results. The request must be
   // delayed until the sync cycle has completed.
-  // TODO(noyau): This might happen too often, need a way to coalesce and delay
-  // the notifications.
-  if (model_->loaded())
-    TriggerTokenRequest(false);
+  if (model_->loaded()) {
+    if (observers_.might_have_observers()) {
+      TriggerTokenRequest(false);
+      sync_refresh_skipped_ = false;
+    } else {
+      sync_refresh_skipped_ = true;
+    }
+  }
 }
 
 }  // namespace enhanced_bookmarks