MD Settings: Add "Show Google Now cards in the launcher" row in Search section.

chrome/browser/ui/webui/settings/search_engines_handler.cc

 // Copyright 2016 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/ui/webui/settings/search_engines_handler.h"
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/extension_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/hotword_audio_history_handler.h"
 #include "chrome/browser/search/hotword_service.h"
 #include "chrome/browser/search/hotword_service_factory.h"
 #include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/browser/search_engines/ui_thread_search_terms_data.h"
@@ skipping 43 matching lines @@
          url_template->url_ref().HasGoogleBaseURLs(
              template_url_service->search_terms_data());
 }
 
 bool GetHotwordAlwaysOn(Profile* profile) {
   SigninManagerBase* signin = SigninManagerFactory::GetForProfile(profile);
   return signin && signin->IsAuthenticated() &&
          HotwordServiceFactory::IsAlwaysOnAvailable();
 }
 
+bool IsGoogleNowAvailable(Profile* profile) {
+  std::string group = base::FieldTrialList::FindFullName("GoogleNowExtension");
+  bool has_field_trial = !group.empty() && group != "Disabled";
+  return has_field_trial && IsGoogleDefaultSearch(profile);
+}
+
 }  // namespace
 
 namespace settings {
 
 SearchEnginesHandler::SearchEnginesHandler(Profile* profile)
     : profile_(profile), list_controller_(profile), weak_ptr_factory_(this) {
   pref_change_registrar_.Init(profile_->GetPrefs());
 }
 
 SearchEnginesHandler::~SearchEnginesHandler() {
@@ skipping 31 matching lines @@
       "searchEngineEditCompleted",
       base::Bind(&SearchEnginesHandler::HandleSearchEngineEditCompleted,
                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback(
       "getHotwordInfo", base::Bind(&SearchEnginesHandler::HandleGetHotwordInfo,
                                    base::Unretained(this)));
   web_ui()->RegisterMessageCallback(
       "setHotwordSearchEnabled",
       base::Bind(&SearchEnginesHandler::HandleSetHotwordSearchEnabled,
                  base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "getGoogleNowAvailability",
+      base::Bind(&SearchEnginesHandler::HandleGetGoogleNowAvailability,
+                 base::Unretained(this)));
 }
 
 void SearchEnginesHandler::OnJavascriptAllowed() {
   list_controller_.table_model()->SetObserver(this);
   pref_change_registrar_.Add(prefs::kHotwordSearchEnabled,
                              base::Bind(&SearchEnginesHandler::SendHotwordInfo,
                                         base::Unretained(this)));
   pref_change_registrar_.Add(prefs::kHotwordAlwaysOnSearchEnabled,
                              base::Bind(&SearchEnginesHandler::SendHotwordInfo,
                                         base::Unretained(this)));
@@ skipping 46 matching lines @@
   search_engines_info->Set("extensions",
                            base::WrapUnique(extensions.release()));
   return search_engines_info;
 }
 
 void SearchEnginesHandler::OnModelChanged() {
   AllowJavascript();
   CallJavascriptFunction("cr.webUIListenerCallback",
                          base::StringValue("search-engines-changed"),
                          *GetSearchEnginesList());
+  // Google Now availability may have changed.
+  CallJavascriptFunction(
+      "cr.webUIListenerCallback",
+      base::StringValue("google-now-availability-changed"),
+      base::FundamentalValue(IsGoogleNowAvailable(profile_)));
 }
 
 void SearchEnginesHandler::OnItemsChanged(int start, int length) {
   OnModelChanged();
 }
 
 void SearchEnginesHandler::OnItemsAdded(int start, int length) {
   OnModelChanged();
 }
 
@@ skipping 226 matching lines @@
 
   // OnGetHotwordAudioHistoryEnabled will call HotwordInfoComplete().
   HotwordServiceFactory::GetForProfile(profile_)
       ->GetAudioHistoryHandler()
       ->GetAudioHistoryEnabled(
           base::Bind(&SearchEnginesHandler::OnGetHotwordAudioHistoryEnabled,
                      weak_ptr_factory_.GetWeakPtr(), base::Passed(&callback_id),
                      base::Passed(&status)));
 }
 
+void SearchEnginesHandler::HandleGetGoogleNowAvailability(
+    const base::ListValue* args) {
+  CHECK_EQ(1U, args->GetSize());
+  const base::Value* callback_id;
+  CHECK(args->Get(0, &callback_id));
+  AllowJavascript();
+  ResolveJavascriptCallback(
+      *callback_id, base::FundamentalValue(IsGoogleNowAvailable(profile_)));
+}
+
 std::unique_ptr<base::DictionaryValue> SearchEnginesHandler::GetHotwordInfo() {
   auto status = base::MakeUnique<base::DictionaryValue>();
   if (!IsGoogleDefaultSearch(profile_)) {
     status->SetBoolean(kHotwordSatusAllowed, false);
     return status;
   }
 
   status->SetBoolean(kHotwordSatusAllowed,
                      HotwordServiceFactory::IsHotwordAllowed(profile_));
 
@@ skipping 86 matching lines @@
     bool logging_enabled =
         profile_->GetPrefs()->GetBoolean(prefs::kHotwordAudioLoggingEnabled);
     launch_mode = logging_enabled ? HotwordService::HOTWORD_ONLY
                                   : HotwordService::HOTWORD_AND_AUDIO_HISTORY;
   }
   hotword_service->OptIntoHotwording(launch_mode);
   SendHotwordInfo();
 }
 
 }  // namespace settings