[iOS] Upstream preference names used by iOS

ios/chrome/browser/pref_names.h

Index: ios/chrome/browser/pref_names.h
diff --git a/ios/chrome/browser/pref_names.h b/ios/chrome/browser/pref_names.h
index 95ede81ae1ffdaad1ae191fcf56d9e81c7dd152e..4b39f45c41042440479293c85825a9f954727aff 100644
--- a/ios/chrome/browser/pref_names.h
+++ b/ios/chrome/browser/pref_names.h
@@ -17,11 +17,31 @@ extern const char kAcceptLanguages[];
 
 namespace prefs {
 
+extern const char kContextualSearchEnabled[];
 extern const char kIosBookmarkFolderDefault[];
 extern const char kIosBookmarkPromoAlreadySeen[];
+extern const char kIosHandoffToOtherDevices[];
+extern const char kMetricsReportingWifiOnly[];
+extern const char kNetworkPredictionWifiOnly[];
+extern const char kNtpShownBookmarksFolder[];
 extern const char kPaymentsPreferredUserId[];
 extern const char kShowMemoryDebuggingTools[];
 
+extern const char kVoiceSearchLocale[];
+extern const char kVoiceSearchTTS[];
+
+extern const char kSigninLastAccounts[];
+extern const char kSigninSharedAuthenticationUserId[];
+extern const char kSigninShouldPromptForSigninAgain[];
+
+extern const char kOmniboxGeolocationAuthorizationState[];
+extern const char kOmniboxGeolocationLastAuthorizationAlertVersion[];
+
+extern const char kDoodleAltText[];
+extern const char kDoodleExpirationTimeInSeconds[];
+extern const char kDoodleHref[];
+extern const char kDoodleLastRequestTimeInSeconds[];
+
 }  // namespace prefs
 
 #endif  // IOS_CHROME_BROWSER_PREF_NAMES_H_