[sync] Check against nullptr web_data_backend->GetDatabase()

components/autofill/core/browser/webdata/autocomplete_sync_bridge.cc

Index: components/autofill/core/browser/webdata/autocomplete_sync_bridge.cc
diff --git a/components/autofill/core/browser/webdata/autocomplete_sync_bridge.cc b/components/autofill/core/browser/webdata/autocomplete_sync_bridge.cc
index df12ab1add44935e2791a2fd862e767b7672585b..21653cc12c016b66b10699f61f4862c71380e064 100644
--- a/components/autofill/core/browser/webdata/autocomplete_sync_bridge.cc
+++ b/components/autofill/core/browser/webdata/autocomplete_sync_bridge.cc
@@ -449,6 +449,13 @@ void AutocompleteSyncBridge::ActOnLocalChanges(
 
 void AutocompleteSyncBridge::LoadMetadata() {
   auto batch = base::MakeUnique<syncer::MetadataBatch>();

[skym, 2017/05/08 22:22:13]

Why make the batch first?

[Patrick Noland, 2017/05/08 22:36:33]

Done.

+  if (!web_data_backend_ || !web_data_backend_->GetDatabase() ||
+      !GetAutofillTable()) {
+    change_processor()->ReportError(FROM_HERE,
+                                    "Failed to load AutofillWebDatabase.");
+    return;
+  }
+
   if (!GetAutofillTable()->GetAllSyncMetadata(syncer::AUTOFILL, batch.get())) {
     change_processor()->ReportError(
         FROM_HERE, "Failed reading autofill metadata from WebDatabase.");