Create a --disable-top-sites flag for use by telemetry tests

chrome/browser/history/top_sites_factory.cc

 // Copyright 2015 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/history/top_sites_factory.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/macros.h"
 #include "base/memory/singleton.h"
 #include "build/build_config.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/history/history_utils.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/grit/chromium_strings.h"
 #include "chrome/grit/generated_resources.h"
 #include "chrome/grit/locale_settings.h"
 #include "components/history/core/browser/history_constants.h"
 #include "components/history/core/browser/top_sites_impl.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "content/public/browser/browser_thread.h"
 #include "grit/theme_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "url/gurl.h"
 
 namespace {
 
+const char kDisableTopSites[] = "disable-top-sites";
+
+bool IsTopSitesDisabled() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(kDisableTopSites);
+}
+
 struct RawPrepopulatedPage {
   int url_id;        // The resource for the page URL.
   int title_id;      // The resource for the page title.
   int favicon_id;    // The raw data resource for the favicon.
   int thumbnail_id;  // The raw data resource for the thumbnail.
   SkColor color;     // The best color to highlight the page (should roughly
                      // match favicon).
 };
 
 #if !defined(OS_ANDROID)
@@ skipping 29 matching lines @@
         page.thumbnail_id, page.color));
   }
 #endif
 }
 
 }  // namespace
 
 // static
 scoped_refptr<history::TopSites> TopSitesFactory::GetForProfile(
     Profile* profile) {
+  if (IsTopSitesDisabled())
+    return nullptr;
   return static_cast<history::TopSites*>(
       GetInstance()->GetServiceForBrowserContext(profile, true).get());
 }
 
 // static
 TopSitesFactory* TopSitesFactory::GetInstance() {
   return base::Singleton<TopSitesFactory>::get();
 }
 
 // static
@@ skipping 29 matching lines @@
 }
 
 void TopSitesFactory::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   history::TopSitesImpl::RegisterPrefs(registry);
 }
 
 bool TopSitesFactory::ServiceIsNULLWhileTesting() const {
   return true;
 }