[Sync] Convert DTCs to be not RefCounted and NonThreadSafe.

components/sync_sessions/session_data_type_controller.cc

Index: components/sync_sessions/session_data_type_controller.cc
diff --git a/components/sync_sessions/session_data_type_controller.cc b/components/sync_sessions/session_data_type_controller.cc
index b2a7abc6a751e5bc30872224a0f09a00c8e47622..5f88d4ec8a00da425846330a32ae5d42939c5792 100644
--- a/components/sync_sessions/session_data_type_controller.cc
+++ b/components/sync_sessions/session_data_type_controller.cc
@@ -4,6 +4,8 @@
 
 #include "components/sync_sessions/session_data_type_controller.h"
 
+#include <set>
+
 #include "components/prefs/pref_service.h"
 #include "components/sync/driver/sync_client.h"
 #include "components/sync_sessions/sync_sessions_client.h"
@@ -13,15 +15,11 @@
 namespace browser_sync {
 
 SessionDataTypeController::SessionDataTypeController(
-    const scoped_refptr<base::SingleThreadTaskRunner>& ui_thread,
-    const base::Closure& error_callback,
+    const base::Closure& dump_stack,
     sync_driver::SyncClient* sync_client,
     sync_driver::LocalDeviceInfoProvider* local_device,
     const char* history_disabled_pref_name)
-    : UIDataTypeController(ui_thread,
-                           error_callback,
-                           syncer::SESSIONS,
-                           sync_client),
+    : UIDataTypeController(syncer::SESSIONS, dump_stack, sync_client),
       sync_client_(sync_client),
       local_device_(local_device),
       history_disabled_pref_name_(history_disabled_pref_name),
@@ -32,13 +30,13 @@ SessionDataTypeController::SessionDataTypeController(
   pref_registrar_.Add(
       history_disabled_pref_name_,
       base::Bind(&SessionDataTypeController::OnSavingBrowserHistoryPrefChanged,
-                 base::Unretained(this)));
+                 base::AsWeakPtr(this)));
 }
 
 SessionDataTypeController::~SessionDataTypeController() {}
 
 bool SessionDataTypeController::StartModels() {
-  DCHECK(ui_thread()->BelongsToCurrentThread());
+  DCHECK(CalledOnValidThread());
   browser_sync::SyncedWindowDelegatesGetter* synced_window_getter =
       sync_client_->GetSyncSessionsClient()->GetSyncedWindowDelegatesGetter();
   std::set<const browser_sync::SyncedWindowDelegate*> window =
@@ -53,8 +51,9 @@ bool SessionDataTypeController::StartModels() {
   }
 
   if (!local_device_->GetLocalDeviceInfo()) {
-    subscription_ = local_device_->RegisterOnInitializedCallback(base::Bind(
-        &SessionDataTypeController::OnLocalDeviceInfoInitialized, this));
+    subscription_ = local_device_->RegisterOnInitializedCallback(
+        base::Bind(&SessionDataTypeController::OnLocalDeviceInfoInitialized,
+                   base::AsWeakPtr(this)));
     waiting_on_local_device_info_ = true;
   }
 
@@ -62,17 +61,18 @@ bool SessionDataTypeController::StartModels() {
 }
 
 void SessionDataTypeController::StopModels() {
+  DCHECK(CalledOnValidThread());
   subscription_.reset();
 }
 
 bool SessionDataTypeController::ReadyForStart() const {
-  DCHECK(ui_thread()->BelongsToCurrentThread());
+  DCHECK(CalledOnValidThread());
   return !sync_client_->GetPrefService()->GetBoolean(
       history_disabled_pref_name_);
 }
 
 void SessionDataTypeController::OnSessionRestoreComplete() {
-  DCHECK(ui_thread()->BelongsToCurrentThread());
+  DCHECK(CalledOnValidThread());
   waiting_on_session_restore_ = false;
   MaybeCompleteLoading();
 }
@@ -88,7 +88,7 @@ void SessionDataTypeController::MaybeCompleteLoading() {
 }
 
 void SessionDataTypeController::OnLocalDeviceInfoInitialized() {
-  DCHECK(ui_thread()->BelongsToCurrentThread());
+  DCHECK(CalledOnValidThread());
   subscription_.reset();
 
   waiting_on_local_device_info_ = false;
@@ -96,7 +96,7 @@ void SessionDataTypeController::OnLocalDeviceInfoInitialized() {
 }
 
 void SessionDataTypeController::OnSavingBrowserHistoryPrefChanged() {
-  DCHECK(ui_thread()->BelongsToCurrentThread());
+  DCHECK(CalledOnValidThread());
   if (sync_client_->GetPrefService()->GetBoolean(history_disabled_pref_name_)) {
     // If history and tabs persistence is turned off then generate an
     // unrecoverable error. SESSIONS won't be a registered type on the next
@@ -106,7 +106,7 @@ void SessionDataTypeController::OnSavingBrowserHistoryPrefChanged() {
           FROM_HERE, syncer::SyncError::DATATYPE_POLICY_ERROR,
           "History and tab saving is now disabled by policy.",
           syncer::SESSIONS);
-      OnSingleDataTypeUnrecoverableError(error);
+      CreateErrorHandler()->OnUnrecoverableError(error);
     }
   }
 }