Merge to m55: Geneneralized fix for serialization error/reset issues

chrome/renderer/extensions/automation_internal_custom_bindings.cc

Index: chrome/renderer/extensions/automation_internal_custom_bindings.cc
diff --git a/chrome/renderer/extensions/automation_internal_custom_bindings.cc b/chrome/renderer/extensions/automation_internal_custom_bindings.cc
index 221c166b9f8f63a27b781a7524c0c49ac5cefe25..6db09b8295d5d92503d17023f6c7444f81cf7e98 100644
--- a/chrome/renderer/extensions/automation_internal_custom_bindings.cc
+++ b/chrome/renderer/extensions/automation_internal_custom_bindings.cc
@@ -1145,8 +1145,15 @@ void AutomationInternalCustomBindings::OnAccessibilityEvent(
   // Update the internal state whether it's the active profile or not.
   cache->location_offset = params.location_offset;
   deleted_node_ids_.clear();
+  v8::Isolate* isolate = GetIsolate();
+  v8::HandleScope handle_scope(isolate);
+  v8::Context::Scope context_scope(context()->v8_context());
+  v8::Local<v8::Array> args(v8::Array::New(GetIsolate(), 1U));
   if (!cache->tree.Unserialize(params.update)) {
     LOG(ERROR) << cache->tree.error();
+    args->Set(0U, v8::Number::New(isolate, tree_id));
+    context()->DispatchEvent(
+        "automationInternal.onAccessibilityTreeSerializationError", args);
     return;
   }
 
@@ -1157,10 +1164,6 @@ void AutomationInternalCustomBindings::OnAccessibilityEvent(
   SendNodesRemovedEvent(&cache->tree, deleted_node_ids_);
   deleted_node_ids_.clear();
 
-  v8::Isolate* isolate = GetIsolate();
-  v8::HandleScope handle_scope(isolate);
-  v8::Context::Scope context_scope(context()->v8_context());
-  v8::Local<v8::Array> args(v8::Array::New(GetIsolate(), 1U));
   v8::Local<v8::Object> event_params(v8::Object::New(GetIsolate()));
   event_params->Set(CreateV8String(isolate, "treeID"),
                     v8::Integer::New(GetIsolate(), params.tree_id));