Set null testing Favicon factories on iOS too

ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc

Index: ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc
diff --git a/ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc b/ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc
index 1125c07da7be756318836eb18c28617118983589..5d01fb2c2fd665845f459159dc76b5b57852f3f8 100644
--- a/ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc
+++ b/ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.cc
@@ -32,7 +32,9 @@ IOSChromeLargeIconServiceFactory::GetInstance() {
 IOSChromeLargeIconServiceFactory::IOSChromeLargeIconServiceFactory()
     : BrowserStateKeyedServiceFactory(
           "LargeIconService",
-          BrowserStateDependencyManager::GetInstance()) {}
+          BrowserStateDependencyManager::GetInstance()) {
+  DependsOn(ios::FaviconServiceFactory::GetInstance());
+}
 
 IOSChromeLargeIconServiceFactory::~IOSChromeLargeIconServiceFactory() {}
 
@@ -52,3 +54,7 @@ web::BrowserState* IOSChromeLargeIconServiceFactory::GetBrowserStateToUse(
     web::BrowserState* context) const {
   return GetBrowserStateOwnInstanceInIncognito(context);
 }
+
+bool IOSChromeLargeIconServiceFactory::ServiceIsNULLWhileTesting() const {
+  return true;
+}