Replace FTS in the history_service with a brute force text search.

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 2817a98d0a7c23dcd9fd354ca4932055176d459c..d7d4fc492a2b4347367e66356d8a9342487aa3f1 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -1114,6 +1114,14 @@ bool HistoryBackend::GetVisitsForURL(URLID id, VisitVector* visits) {
   return false;
 }
 
+bool HistoryBackend::GetVisitsForURLWithOptions(URLID id,
+                                                const QueryOptions& options,
+                                                VisitVector* visits) {
+  if (db_)
+    return db_->GetVisitsForURLWithOptions(id, options, visits);
+  return false;
+}
+
 bool HistoryBackend::GetMostRecentVisitsForURL(URLID id,
                                                int max_visits,
                                                VisitVector* visits) {
@@ -1402,8 +1410,9 @@ void HistoryBackend::QueryHistory(scoped_refptr<QueryHistoryRequest> request,
       // if (archived_db_.get() &&
       //     expirer_.GetCurrentArchiveTime() - TimeDelta::FromDays(7)) {
     } else {
-      // Full text history query.
-      QueryHistoryFTS(text_query, options, &request->value);
+      // Text history query.
+      QueryHistoryText(db_.get(), db_.get(), text_query, options,
+                       &request->value);
     }
   }
 
@@ -1468,6 +1477,45 @@ void HistoryBackend::QueryHistoryBasic(URLDatabase* url_db,
     result->set_reached_beginning(true);
 }
 
+// Text-based querying of history.
+void HistoryBackend::QueryHistoryText(URLDatabase* url_db,
+                                      VisitDatabase* visit_db,
+                                      const string16& text_query,
+                                      const QueryOptions& options,
+                                      QueryResults* result) {
+  URLRows text_matches;
+  url_db->GetTextMatches(text_query, &text_matches);
+
+  bool too_many = false;
+  std::vector<URLResult> matching_visits;
+  VisitVector visits;    // Declare outside loop to prevent re-construction.
+  for (size_t i = 0; (i < text_matches.size()) && !too_many; i++) {
+    // Get all visits for given URL match.
+    GetVisitsForURLWithOptions(text_matches[i].id(), options, &visits);
+
+    for (size_t j = 0; j < visits.size(); j++) {
+      if (options.max_count != 0 &&
+      static_cast<int>(result->size()) >= options.max_count) {

[Scott Hess - ex-Googler, 2013/06/13 19:45:58]

Indentation.

Also, it might read cleaner to capture a size_t-cast version of max_count above
the loop - you could even set it to std::numeric_limits<size_t>::max() if 0.

[rmcilroy, 2013/06/14 12:45:41]

Done.

+        too_many = true;  // Got too many items.
+        break;
+      }
+      URLResult url_result(text_matches[i]);
+      url_result.set_visit_time(visits[j].visit_time);
+      matching_visits.push_back(url_result);
+    }
+  }
+
+  std::sort(matching_visits.begin(), matching_visits.end(),
+            URLResult::CompareVisitTime);

[Scott Hess - ex-Googler, 2013/06/13 19:45:58]

It seems like this is sorting by visit time AFTER it has trimmed by max_count,
which seems backwards.  It does put the most-relevant stuff first, but there
could be relevant stuff later on which isn't reached in the first place.  Is
that intentional?

[I see that the FTS version did this.  And I don't understand the manual join
being done here.  So I'm asking just to make sure it was considered.]

[rmcilroy, 2013/06/14 12:45:41]

Good point, it makes more sense to trim after sorting by time. Done. 

+  for (std::vector<URLResult>::iterator it = matching_visits.begin();
+       it != matching_visits.end(); ++it) {
+    result->AppendURLBySwapping(&(*it));
+  }
+
+  if (!too_many && options.begin_time <= first_recorded_time_)
+    result->set_reached_beginning(true);
+}
+
 void HistoryBackend::QueryHistoryFTS(const string16& text_query,
                                      const QueryOptions& options,
                                      QueryResults* result) {