Fixed minor bug with Search.DefaultSearchChangeOrigin histogram

chrome/browser/search_engines/template_url_service_unittest.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 "components/search_engines/template_url_service.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/run_loop.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task/cancelable_task_tracker.h"
+#include "base/test/histogram_tester.h"
 #include "base/test/simple_test_clock.h"
 #include "base/threading/thread.h"
 #include "base/time/time.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/search_engines/template_url_service_test_util.h"
 #include "chrome/test/base/testing_profile.h"
 #include "components/history/core/browser/history_service.h"
 #include "components/search_engines/keyword_web_data_service.h"
 #include "components/search_engines/search_engines_pref_names.h"
 #include "components/search_engines/search_engines_test_util.h"
@@ skipping 1904 matching lines @@
   TemplateURL* update_url =
       model()->GetTemplateURLForKeyword(ASCIIToUTF16("engine_keyword"));
   const Time update_last_modified = update_url->last_modified();
   model()->SetUserSelectedDefaultSearchProvider(update_url);
   TemplateURL* reloaded_url =
       model()->GetTemplateURLForKeyword(ASCIIToUTF16("engine_keyword"));
   const Time reloaded_last_modified = reloaded_url->last_modified();
   EXPECT_NE(original_last_modified, reloaded_last_modified);
   EXPECT_EQ(update_last_modified, reloaded_last_modified);
 }
+
+// Tests checks that Search.DefaultSearchChangeOrigin histogram is correctly
+// emitted when TemplateURLService is not yet loaded.

[Peter Kasting, 2017/04/14 08:02:00]

Another way of testing would be to verify that
TemplateURLService::dsp_change_callback_ is run in this case.  This is probably
more important to get right than the histogram, though testing it might be
annoying.

+TEST_F(TemplateURLServiceTest, ChangeDefaultEngineBeforeLoad) {
+  TemplateURL* search_engine1 = model()->Add(
+      base::MakeUnique<TemplateURL>(*GenerateDummyTemplateURLData("keyword1")));
+  DCHECK(search_engine1);
+  TemplateURL* search_engine2 = model()->Add(
+      base::MakeUnique<TemplateURL>(*GenerateDummyTemplateURLData("keyword2")));
+  DCHECK(search_engine2);
+
+  base::HistogramTester histogram_tester;
+  model()->SetUserSelectedDefaultSearchProvider(search_engine1);
+  histogram_tester.ExpectTotalCount("Search.DefaultSearchChangeOrigin", 1);
+  model()->SetUserSelectedDefaultSearchProvider(search_engine1);
+  histogram_tester.ExpectTotalCount("Search.DefaultSearchChangeOrigin", 1);
+  model()->SetUserSelectedDefaultSearchProvider(search_engine2);
+  histogram_tester.ExpectTotalCount("Search.DefaultSearchChangeOrigin", 2);
+}