[Fallback Icons] Refactor FallbackIconService to be a BrowserContext-level singleton

chrome/test/base/testing_profile.cc

Index: chrome/test/base/testing_profile.cc
diff --git a/chrome/test/base/testing_profile.cc b/chrome/test/base/testing_profile.cc
index 004a73ceaee378c502170e11c465f7d773876254..d33aeefbf4533ab521a328a0dcf8e1e26bdf6a2d 100644
--- a/chrome/test/base/testing_profile.cc
+++ b/chrome/test/base/testing_profile.cc
@@ -20,7 +20,9 @@
 #include "chrome/browser/bookmarks/chrome_bookmark_client_factory.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/favicon/chrome_fallback_icon_client_factory.h"
 #include "chrome/browser/favicon/chrome_favicon_client_factory.h"
+#include "chrome/browser/favicon/fallback_icon_service_factory.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/history/chrome_history_client.h"
 #include "chrome/browser/history/chrome_history_client_factory.h"
@@ -54,6 +56,7 @@
 #include "components/bookmarks/browser/bookmark_model.h"
 #include "components/bookmarks/common/bookmark_constants.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
+#include "components/favicon/core/fallback_icon_service.h"
 #include "components/favicon/core/favicon_service.h"
 #include "components/history/content/browser/content_visit_delegate.h"
 #include "components/history/content/browser/history_database_helper.h"
@@ -213,6 +216,12 @@ KeyedService* CreateTestDesktopNotificationService(
 }
 #endif
 
+KeyedService* BuildFallbackIconService(content::BrowserContext* context) {
+  Profile* profile = Profile::FromBrowserContext(context);
+  return new FallbackIconService(
+      ChromeFallbackIconClientFactory::GetForBrowserContext(profile));
+}
+
 KeyedService* BuildFaviconService(content::BrowserContext* context) {
   Profile* profile = Profile::FromBrowserContext(context);
   return new FaviconService(ChromeFaviconClientFactory::GetForProfile(profile),
@@ -570,6 +579,11 @@ TestingProfile::~TestingProfile() {
   }
 }
 
+void TestingProfile::CreateFallbackIconService() {
+  FaviconServiceFactory::GetInstance()->SetTestingFactory(
+      this, BuildFallbackIconService);
+}
+
 void TestingProfile::CreateFaviconService() {
   // It is up to the caller to create the history service if one is needed.
   FaviconServiceFactory::GetInstance()->SetTestingFactory(