[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 f77bdee6c570c22e738017d1224ebc2b98dd0962..2f290512c0ececce06fd5f45d8199d14d613b5ef 100644
--- a/chrome/test/base/testing_profile.cc
+++ b/chrome/test/base/testing_profile.cc
@@ -19,6 +19,8 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/favicon/chrome_favicon_client_factory.h"
+#include "chrome/browser/favicon/fallback_icon_service.h"
+#include "chrome/browser/favicon/fallback_icon_service_factory.h"
 #include "chrome/browser/favicon/favicon_service.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/history/chrome_history_client.h"
@@ -211,6 +213,13 @@ KeyedService* CreateTestDesktopNotificationService(
 }
 #endif
 
+KeyedService* BuildFallbackIconService(content::BrowserContext* profile) {
+  FallbackIconClient* fallback_icon_client =
+      ChromeFallbackIconClientFactory::GetForProfile(
+          static_cast<Profile*>(profile));
+  return new FallbackIconService(fallback_icon_client);
+}
+
 KeyedService* BuildFaviconService(content::BrowserContext* profile) {
   FaviconClient* favicon_client =
       ChromeFaviconClientFactory::GetForProfile(static_cast<Profile*>(profile));
@@ -554,6 +563,11 @@ 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(