[Sync] Refactor sync datatype error handling.

chrome/browser/sync/glue/generic_change_processor.cc

Index: chrome/browser/sync/glue/generic_change_processor.cc
diff --git a/chrome/browser/sync/glue/generic_change_processor.cc b/chrome/browser/sync/glue/generic_change_processor.cc
index 6c85de91ba0779b2eaa70619ff078c99d95c4c2f..d24d4779c6fb36f10b5a621664c37179e4a5b78d 100644
--- a/chrome/browser/sync/glue/generic_change_processor.cc
+++ b/chrome/browser/sync/glue/generic_change_processor.cc
@@ -7,6 +7,7 @@
 #include "base/tracked.h"
 #include "chrome/browser/sync/api/syncable_service.h"
 #include "chrome/browser/sync/api/sync_change.h"
+#include "chrome/browser/sync/api/sync_error.h"
 #include "chrome/browser/sync/engine/syncapi.h"
 #include "chrome/browser/sync/syncable/nigori_util.h"
 
@@ -69,37 +70,45 @@ void GenericChangeProcessor::CommitChangesFromSyncModel() {
     return;
   if (syncer_changes_.empty())
     return;
-  local_service_->ProcessSyncChanges(FROM_HERE, syncer_changes_);
+  SyncError error = local_service_->ProcessSyncChanges(FROM_HERE,
+                                                        syncer_changes_);
   syncer_changes_.clear();
+  if (error.IsSet()) {
+    error_handler()->OnUnrecoverableError(error.location(), error.message());
+  }
 }
 
-bool GenericChangeProcessor::GetSyncDataForType(
+SyncError GenericChangeProcessor::GetSyncDataForType(
     syncable::ModelType type,
     SyncDataList* current_sync_data) {
   std::string type_name = syncable::ModelTypeToString(type);
   sync_api::ReadTransaction trans(FROM_HERE, share_handle());
   sync_api::ReadNode root(&trans);
   if (!root.InitByTagLookup(syncable::ModelTypeToRootTag(type))) {
-    LOG(ERROR) << "Server did not create the top-level " + type_name + " node."
-               << " We might be running against an out-of-date server.";
-    return false;
+    SyncError error(FROM_HERE,
+                    "Server did not create the top-level " + type_name +
+                    " node. We might be running against an out-of-date server.",
+                    type);
+    return error;
   }
 
   int64 sync_child_id = root.GetFirstChildId();
   while (sync_child_id != sync_api::kInvalidId) {
     sync_api::ReadNode sync_child_node(&trans);
     if (!sync_child_node.InitByIdLookup(sync_child_id)) {
-      LOG(ERROR) << "Failed to fetch child node for type " + type_name + ".";
-      return false;
+      SyncError error(FROM_HERE,
+                      "Failed to fetch child node for type " + type_name + ".",
+                       type);
+      return error;
     }
     current_sync_data->push_back(SyncData::CreateRemoteData(
         sync_child_node.GetEntitySpecifics()));
     sync_child_id = sync_child_node.GetSuccessorId();
   }
-  return true;
+  return SyncError();
 }
 
-void GenericChangeProcessor::ProcessSyncChanges(
+SyncError GenericChangeProcessor::ProcessSyncChanges(
     const tracked_objects::Location& from_here,
     const SyncChangeList& list_of_changes) {
   sync_api::WriteTransaction trans(from_here, share_handle());
@@ -109,17 +118,20 @@ void GenericChangeProcessor::ProcessSyncChanges(
        ++iter) {
     const SyncChange& change = *iter;
     DCHECK_NE(change.sync_data().GetDataType(), syncable::UNSPECIFIED);
-    std::string type_str = syncable::ModelTypeToString(
-        change.sync_data().GetDataType());
+    syncable::ModelType type = change.sync_data().GetDataType();
+    std::string type_str = syncable::ModelTypeToString(type);
     sync_api::WriteNode sync_node(&trans);
     if (change.change_type() == SyncChange::ACTION_DELETE) {
       if (change.sync_data().GetTag() == "" ||
           !sync_node.InitByClientTagLookup(change.sync_data().GetDataType(),
                                            change.sync_data().GetTag())) {
         NOTREACHED();
-        error_handler()->OnUnrecoverableError(FROM_HERE,
-            "Failed to delete " + type_str + " node.");
-        return;
+        SyncError error(FROM_HERE,
+                        "Failed to delete " + type_str + " node.",
+                        type);
+        error_handler()->OnUnrecoverableError(error.location(),
+                                              error.message());
+        return error;
       }
       sync_node.Remove();
     } else if (change.change_type() == SyncChange::ACTION_ADD) {
@@ -129,16 +141,23 @@ void GenericChangeProcessor::ProcessSyncChanges(
       if (!root_node.InitByTagLookup(
               syncable::ModelTypeToRootTag(change.sync_data().GetDataType()))) {
         NOTREACHED();
-        error_handler()->OnUnrecoverableError(FROM_HERE,
-            "Failed to look up root node for type " + type_str);
-        return;
+        SyncError error(FROM_HERE,
+                        "Failed to look up root node for type " + type_str,
+                        type);
+        error_handler()->OnUnrecoverableError(error.location(),
+                                              error.message());
+        return error;
       }
       if (!sync_node.InitUniqueByCreation(change.sync_data().GetDataType(),
                                           root_node,
                                           change.sync_data().GetTag())) {
-        error_handler()->OnUnrecoverableError(FROM_HERE,
-            "Failed to create " + type_str + " node.");
-        return;
+        NOTREACHED();
+        SyncError error(FROM_HERE,
+                        "Failed to create " + type_str + " node.",
+                        type);
+        error_handler()->OnUnrecoverableError(error.location(),
+                                              error.message());
+        return error;
       }
       sync_node.SetTitle(UTF8ToWide(change.sync_data().GetTitle()));
       sync_node.SetEntitySpecifics(change.sync_data().GetSpecifics());
@@ -147,9 +166,12 @@ void GenericChangeProcessor::ProcessSyncChanges(
           !sync_node.InitByClientTagLookup(change.sync_data().GetDataType(),
                                            change.sync_data().GetTag())) {
         NOTREACHED();
-        error_handler()->OnUnrecoverableError(FROM_HERE,
-            "Failed to update " + type_str + " node");
-        return;
+        SyncError error(FROM_HERE,
+                        "Failed to update " + type_str + " node.",
+                        type);
+        error_handler()->OnUnrecoverableError(error.location(),
+                                              error.message());
+        return error;
       }
       sync_node.SetTitle(UTF8ToWide(change.sync_data().GetTitle()));
       sync_node.SetEntitySpecifics(change.sync_data().GetSpecifics());
@@ -157,11 +179,15 @@ void GenericChangeProcessor::ProcessSyncChanges(
       // successor, parent, etc.).
     } else {
       NOTREACHED();
-      error_handler()->OnUnrecoverableError(FROM_HERE,
-          "Received unset SyncChange in the change processor.");
-      return;
+      SyncError error(FROM_HERE,
+                      "Received unset SyncChange in the change processor.",
+                      type);
+      error_handler()->OnUnrecoverableError(error.location(),
+                                            error.message());
+      return error;
     }
   }
+  return SyncError();
 }
 
 bool GenericChangeProcessor::SyncModelHasUserCreatedNodes(