Introduce HistoryClient interface

chrome/browser/history/history_service_factory.cc

Index: chrome/browser/history/history_service_factory.cc
diff --git a/chrome/browser/history/history_service_factory.cc b/chrome/browser/history/history_service_factory.cc
index 13f137f60611fe466847634efc7373a1b892cebf..84a704a14226c4bed0eddfa4f3963e852ad67d9e 100644
--- a/chrome/browser/history/history_service_factory.cc
+++ b/chrome/browser/history/history_service_factory.cc
@@ -6,12 +6,15 @@
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
+#include "chrome/browser/history/chrome_history_client.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/common/pref_names.h"
 #include "components/bookmarks/browser/bookmark_model.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 
+using history::ChromeHistoryClient;
+
 // static
 HistoryService* HistoryServiceFactory::GetForProfile(
     Profile* profile, Profile::ServiceAccessType sat) {
@@ -20,8 +23,9 @@ HistoryService* HistoryServiceFactory::GetForProfile(
       sat != Profile::EXPLICIT_ACCESS)
     return NULL;
 
-  return static_cast<HistoryService*>(
+  ChromeHistoryClient* history_client = static_cast<ChromeHistoryClient*>(

[blundell, 2014/05/27 09:56:38]

If you're keeping HistoryServiceFactory, I think you might as well keep
HistoryService as a KeyedService, have a ChromeHistoryClientFactory, and have
FaviconService depend on ChromeHistoryClient (at the factory level) to ensure
that the lifetimes work out as desired.

[sdefresne, 2014/05/28 17:10:42]

Done with %s/FaviconService/HistoryService/g.

       GetInstance()->GetServiceForBrowserContext(profile, true));
+  return history_client ? history_client->history_service() : NULL;
 }
 
 // static
@@ -33,15 +37,17 @@ HistoryServiceFactory::GetForProfileIfExists(
       sat != Profile::EXPLICIT_ACCESS)
     return NULL;
 
-  return static_cast<HistoryService*>(
+  ChromeHistoryClient* history_client = static_cast<ChromeHistoryClient*>(
       GetInstance()->GetServiceForBrowserContext(profile, false));
+  return history_client ? history_client->history_service() : NULL;
 }
 
 // static
 HistoryService*
 HistoryServiceFactory::GetForProfileWithoutCreating(Profile* profile) {
-  return static_cast<HistoryService*>(
+  ChromeHistoryClient* history_client = static_cast<ChromeHistoryClient*>(
       GetInstance()->GetServiceForBrowserContext(profile, false));
+  return history_client ? history_client->history_service() : NULL;
 }
 
 // static
@@ -67,12 +73,13 @@ HistoryServiceFactory::~HistoryServiceFactory() {
 KeyedService* HistoryServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = static_cast<Profile*>(context);
-  HistoryService* history_service = new HistoryService(profile);
+  ChromeHistoryClient* history_client = new ChromeHistoryClient(profile);
+  HistoryService* history_service = history_client->history_service();
   if (!history_service->Init(profile->GetPath(),
                              BookmarkModelFactory::GetForProfile(profile))) {
     return NULL;
   }
-  return history_service;
+  return history_client;
 }
 
 content::BrowserContext* HistoryServiceFactory::GetBrowserContextToUse(