Make HistoryQuickProvider::DeleteMatch also delete the underlying URL from the History Database.

chrome/browser/autocomplete/history_provider.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/autocomplete/history_provider.h"
 
 #include <string>
 
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete_input.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/history/in_memory_url_index_types.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/url_constants.h"
 #include "url/url_util.h"
 
 void HistoryProvider::DeleteMatch(const AutocompleteMatch& match) {
   DCHECK(done_);
   DCHECK(profile_);
   DCHECK(match.deletable);
 
   HistoryService* const history_service =
       HistoryServiceFactory::GetForProfile(profile_, Profile::EXPLICIT_ACCESS);
 
-  // Delete the match from the history DB.
+  // Delete the underlying URL along with all its visits from the history DB.
+  // The resulting HISTORY_URLS_DELETED notification will also cause all caches
+  // and indices to drop any data they might have stored pertaining to the URL.
   DCHECK(history_service);
   DCHECK(match.destination_url.is_valid());
   history_service->DeleteURL(match.destination_url);
+
   DeleteMatchFromMatches(match);
 }
 
 // static
 bool HistoryProvider::PreventInlineAutocomplete(
     const AutocompleteInput& input) {
   return input.prevent_inline_autocomplete() ||
       (!input.text().empty() &&
        IsWhitespace(input.text()[input.text().length() - 1]));
 }
@@ skipping 50 matching lines @@
     do {
       offset += matches[i].length;
       ++i;
     } while ((i < match_count) && (offset == matches[i].offset));
     if (offset < text_length)
       spans.push_back(ACMatchClassification(offset, url_style));
   }
 
   return spans;
 }