Added HistoryService::GetHistoryCount() and helper functions in components/history

components/history/core/browser/history_service.cc

Index: components/history/core/browser/history_service.cc
diff --git a/components/history/core/browser/history_service.cc b/components/history/core/browser/history_service.cc
index 28bdd51cdb5cca43617ab5ff20c9656477a6cd05..86822058d0dfc178ad1c673d4c7142b5f3ec309f 100644
--- a/components/history/core/browser/history_service.cc
+++ b/components/history/core/browser/history_service.cc
@@ -667,6 +667,19 @@ base::CancelableTaskTracker::TaskId HistoryService::QueryURL(
                  base::Owned(query_url_result)));
 }
 
+// Statistics ------------------------------------------------------------------

[msramek, 2015/09/14 17:28:16]

nit: Empty line after "---" comment.

[lwchkg, 2015/09/15 14:27:08]

Acknowledged.

+base::CancelableTaskTracker::TaskId HistoryService::GetHistoryCount(
+    const GetHistoryCountCallback& callback,
+    base::CancelableTaskTracker* tracker) {
+  DCHECK(thread_) << "History service being called after cleanup";
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  return tracker->PostTaskAndReplyWithResult(
+      thread_->task_runner().get(), FROM_HERE,
+      base::Bind(&HistoryBackend::GetHistoryCount, history_backend_.get()),
+      callback);
+}
+
 // Downloads -------------------------------------------------------------------
 
 // Handle creation of a download by creating an entry in the history service's