[Sync] Request dependency services in sync client with implicit access type.

chrome/browser/sync/chrome_sync_client.cc

Index: chrome/browser/sync/chrome_sync_client.cc
diff --git a/chrome/browser/sync/chrome_sync_client.cc b/chrome/browser/sync/chrome_sync_client.cc
index 07de94c758c97c79b8074749364b563002c19708..df33a7713b631c797888174278c351637955b352 100644
--- a/chrome/browser/sync/chrome_sync_client.cc
+++ b/chrome/browser/sync/chrome_sync_client.cc
@@ -140,7 +140,7 @@ class SyncSessionsClientImpl : public sync_sessions::SyncSessionsClient {
   favicon::FaviconService* GetFaviconService() override {
     DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     return FaviconServiceFactory::GetForProfile(
-        profile_, ServiceAccessType::EXPLICIT_ACCESS);
+        profile_, ServiceAccessType::IMPLICIT_ACCESS);
   }
   history::HistoryService* GetHistoryService() override {
     DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
@@ -189,10 +189,9 @@ void ChromeSyncClient::Initialize() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   web_data_service_ = WebDataServiceFactory::GetAutofillWebDataForProfile(

[skym, 2016/01/28 20:20:55]

Kinda odd we cache some (webdata/password), but fetch favicon/history on demand.

[pavely, 2016/01/28 22:30:53]

Don't know why. Maybe factory needs to be called on UI thread (since it accesses
profile) while service pointer is exposed on backend thread through
GetSyncableServiceForType.

Another reason could be that instantiating some services incurs costly IO which
we are trying to avoid at startup and ChromeSyncClient gets initialized very
early on.

-      profile_, ServiceAccessType::EXPLICIT_ACCESS);
-  // TODO(crbug.com/558320) Is EXPLICIT_ACCESS appropriate here?
+      profile_, ServiceAccessType::IMPLICIT_ACCESS);
   password_store_ = PasswordStoreFactory::GetForProfile(
-      profile_, ServiceAccessType::EXPLICIT_ACCESS);
+      profile_, ServiceAccessType::IMPLICIT_ACCESS);
 
   // Component factory may already be set in tests.
   if (!GetSyncApiComponentFactory()) {
@@ -235,7 +234,7 @@ bookmarks::BookmarkModel* ChromeSyncClient::GetBookmarkModel() {
 favicon::FaviconService* ChromeSyncClient::GetFaviconService() {

[skym, 2016/01/28 20:20:55]

Why doesn't this just delegate to the sync_sessions_client_? Am I missing
something?

[pavely, 2016/01/28 22:30:53]

To be honest don't know.

   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   return FaviconServiceFactory::GetForProfile(
-      profile_, ServiceAccessType::EXPLICIT_ACCESS);
+      profile_, ServiceAccessType::IMPLICIT_ACCESS);
 }
 
 history::HistoryService* ChromeSyncClient::GetHistoryService() {

[skym, 2016/01/28 20:20:55]

Same delegate question.