Revert of Port HistoryService::GetVisibleVisitCountToHost to CancelableTaskTracker

chrome/browser/history/history_backend.cc

Index: chrome/browser/history/history_backend.cc
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index 17a013e002eb1dc7d91011eb03494c7699d0e629..200b7d19541cbe9383c46960bfa54f67bf969ffb 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -1321,12 +1321,15 @@
 }
 
 void HistoryBackend::GetVisibleVisitCountToHost(
-    const GURL& url,
-    VisibleVisitCountToHostResult* result) {
-  result->count = 0;
-  result->success = db_.get() &&
-                    db_->GetVisibleVisitCountToHost(
-                        url, &result->count, &result->first_visit);
+    scoped_refptr<GetVisibleVisitCountToHostRequest> request,
+    const GURL& url) {
+  if (request->canceled())
+    return;
+  int count = 0;
+  Time first_visit;
+  const bool success = db_.get() &&
+      db_->GetVisibleVisitCountToHost(url, &count, &first_visit);
+  request->ForwardResult(request->handle(), success, count, first_visit);
 }
 
 void HistoryBackend::QueryTopURLsAndRedirects(