Add field to monitor last visited time for each search engine

components/search_engines/template_url_data.cc

 // Copyright 2014 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 "components/search_engines/template_url_data.h"
 
 #include "base/guid.h"
 #include "base/i18n/case_conversion.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 
 TemplateURLData::TemplateURLData()
     : safe_for_autoreplace(false),
       id(0),
       date_created(base::Time::Now()),
       last_modified(base::Time::Now()),
+      last_visited(base::Time::Now()),

[Peter Kasting, 2016/11/21 03:35:08]

Seems wrong to set last_visited to Now() (instead of just to Time()) here, as
then we can't distinguish between an engine which was never visited from one
which has been.

(To phrase differently, I think setting this this way causes every newly-created
engine to appear to be "recently visited".)

[ltian, 2016/11/28 22:08:02]

I think it is related to how we define "recently visited"? If we think if a
search engine is detected but is not used for search could also serve as a
visit, then this setting is the right implementation, but if it is not counted
as a visit, then we should set the filed to Time()?

Change it to set as Time() and will also check with Kingston to make sure this
is the right behavior.

       created_by_policy(false),
       usage_count(0),
       prepopulate_id(0),
       sync_guid(base::GenerateGUID()),
       keyword_(base::ASCIIToUTF16("dummy")),
       url_("x") {}
 
 TemplateURLData::TemplateURLData(const TemplateURLData& other) = default;
 
 TemplateURLData::~TemplateURLData() {
@@ skipping 12 matching lines @@
 
   // Case sensitive keyword matching is confusing. As such, we force all
   // keywords to be lower case.
   keyword_ = base::i18n::ToLower(keyword);
 }
 
 void TemplateURLData::SetURL(const std::string& url) {
   DCHECK(!url.empty());
   url_ = url;
 }