[Sync] Refactor sync datatype error handling.

chrome/browser/prefs/pref_model_associator.cc

Index: chrome/browser/prefs/pref_model_associator.cc
diff --git a/chrome/browser/prefs/pref_model_associator.cc b/chrome/browser/prefs/pref_model_associator.cc
index 5c004a7becc9ae4fea2ad292af6736f21b4720b7..5b954282ad1f818baf5b7e6652628875d0130c1c 100644
--- a/chrome/browser/prefs/pref_model_associator.cc
+++ b/chrome/browser/prefs/pref_model_associator.cc
@@ -119,7 +119,8 @@ void PrefModelAssociator::InitPrefAndAssociate(
 bool PrefModelAssociator::MergeDataAndStartSyncing(
     syncable::ModelType type,
     const SyncDataList& initial_sync_data,
-    SyncChangeProcessor* sync_processor) {
+    SyncChangeProcessor* sync_processor,
+    SyncError* error) {
   DCHECK_EQ(type, PREFERENCES);
   DCHECK(CalledOnValidThread());
   DCHECK(!sync_processor_);
@@ -158,9 +159,12 @@ bool PrefModelAssociator::MergeDataAndStartSyncing(
   }
 
   // Push updates to sync.
-  sync_processor_->ProcessSyncChanges(FROM_HERE, new_changes);
-  models_associated_ = true;
-  return true;
+  if (!sync_processor_->ProcessSyncChanges(FROM_HERE, new_changes, error)) {
+    return false;
+  } else {
+    models_associated_ = true;
+    return true;
+  }
 }
 
 void PrefModelAssociator::StopSyncing(syncable::ModelType type) {
@@ -306,11 +310,16 @@ SyncDataList PrefModelAssociator::GetAllSyncData(syncable::ModelType type)
   return current_data;
 }
 
-void PrefModelAssociator::ProcessSyncChanges(
+bool PrefModelAssociator::ProcessSyncChanges(
     const tracked_objects::Location& from_here,
-    const SyncChangeList& change_list) {
-  if (!models_associated_)
-    return;
+    const SyncChangeList& change_list,
+    SyncError* error) {
+  if (!models_associated_) {
+    error->reset(FROM_HERE,
+                 "Models not yet associated.",
+                 PREFERENCES);
+    return false;
+  }
   AutoReset<bool> processing_changes(&processing_syncer_changes_, true);
   SyncChangeList::const_iterator iter;
   for (iter = change_list.begin(); iter != change_list.end(); ++iter) {
@@ -359,6 +368,7 @@ void PrefModelAssociator::ProcessSyncChanges(
 
     SendUpdateNotificationsIfNecessary(name);
   }
+  return true;
 }
 
 Value* PrefModelAssociator::ReadPreferenceSpecifics(
@@ -432,5 +442,8 @@ void PrefModelAssociator::ProcessPrefChange(const std::string& name) {
     }
     changes.push_back(SyncChange(SyncChange::ACTION_UPDATE, sync_data));
   }
-  sync_processor_->ProcessSyncChanges(FROM_HERE, changes);
+
+  SyncError error;
+  if (!sync_processor_->ProcessSyncChanges(FROM_HERE, changes, &error))
+    StopSyncing(PREFERENCES);
 }