Revert "Revert 182527" ([Sync] Make SESSIONS an implicit type)

chrome/browser/sync/sync_prefs.cc

Index: chrome/browser/sync/sync_prefs.cc
diff --git a/chrome/browser/sync/sync_prefs.cc b/chrome/browser/sync/sync_prefs.cc
index 3d9be89d17f64ea34649e32c0ccdfbeab0d73f30..e2c40ddd12b6d349788d36f2e5791851d85faaee 100644
--- a/chrome/browser/sync/sync_prefs.cc
+++ b/chrome/browser/sync/sync_prefs.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/sync/sync_prefs.h"
 
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/public/pref_member.h"
@@ -14,6 +15,7 @@
 #include "chrome/browser/profiles/profile_io_data.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
@@ -320,6 +322,8 @@ const char* SyncPrefs::GetPrefNameForDataType(syncer::ModelType data_type) {
       return prefs::kSyncFaviconImages;
     case syncer::FAVICON_TRACKING:
       return prefs::kSyncFaviconTracking;
+    case syncer::PROXY_TABS:
+      return prefs::kSyncTabs;
     default:
       break;
   }
@@ -387,13 +391,20 @@ void SyncPrefs::RegisterPrefGroups() {
   pref_groups_[syncer::PREFERENCES].Put(syncer::DICTIONARY);
   pref_groups_[syncer::PREFERENCES].Put(syncer::SEARCH_ENGINES);
 
+  pref_groups_[syncer::TYPED_URLS].Put(syncer::HISTORY_DELETE_DIRECTIVES);
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch(switches::kHistoryEnableFullHistorySync)) {
+    pref_groups_[syncer::TYPED_URLS].Put(syncer::SESSIONS);
+    pref_groups_[syncer::TYPED_URLS].Put(syncer::FAVICON_IMAGES);
+    pref_groups_[syncer::TYPED_URLS].Put(syncer::FAVICON_TRACKING);
+  }
+
+  pref_groups_[syncer::PROXY_TABS].Put(syncer::SESSIONS);
+  pref_groups_[syncer::PROXY_TABS].Put(syncer::FAVICON_IMAGES);
+  pref_groups_[syncer::PROXY_TABS].Put(syncer::FAVICON_TRACKING);
+
   // TODO(zea): put favicons in the bookmarks group as well once it handles
   // those favicons.
-  pref_groups_[syncer::SESSIONS].Put(syncer::FAVICON_IMAGES);
-  pref_groups_[syncer::SESSIONS].Put(syncer::FAVICON_TRACKING);
-
-  // TODO(akalin): Revisit this once UI lands.
-  pref_groups_[syncer::SESSIONS].Put(syncer::HISTORY_DELETE_DIRECTIVES);
 }
 
 // static
@@ -419,6 +430,13 @@ bool SyncPrefs::GetDataTypePreferred(syncer::ModelType type) const {
     NOTREACHED();
     return false;
   }
+  if (type == syncer::PROXY_TABS &&
+      pref_service_->GetUserPrefValue(pref_name) == NULL &&
+      pref_service_->IsUserModifiablePreference(pref_name)) {
+    // If there is no tab sync preference yet (i.e. newly enabled type),
+    // default to the session sync preference value.
+    pref_name = GetPrefNameForDataType(syncer::SESSIONS);
+  }
 
   return pref_service_->GetBoolean(pref_name);
 }
@@ -444,8 +462,6 @@ syncer::ModelTypeSet SyncPrefs::ResolvePrefGroups(
       i != pref_groups_.end(); ++i) {
     if (types.Has(i->first))
       types_with_groups.PutAll(i->second);
-    else
-      types_with_groups.RemoveAll(i->second);
   }
   types_with_groups.RetainAll(registered_types);
   return types_with_groups;