Generalized fix for serialization error/reset issues

chrome/renderer/resources/extensions/automation_custom_bindings.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Custom bindings for the automation API.
 var AutomationNode = require('automationNode').AutomationNode;
 var AutomationRootNode = require('automationNode').AutomationRootNode;
 var automation = require('binding').Binding.create('automation');
 var automationInternal =
     require('binding').Binding.create('automationInternal').generate();
@@ skipping 329 matching lines @@
     privates(targetTree).impl.destroy();
     AutomationRootNode.destroy(id);
   } else {
     logging.WARNING('no targetTree to destroy');
   }
 
   // Destroy the native cache of the accessibility tree.
   DestroyAccessibilityTree(id);
 });
 
+automationInternal.onAccessibilityTreeSerializationError.addListener(function(id) {

[dmazzoni, 2016/11/22 18:11:42]

nit: wrap

[David Tseng, 2016/11/22 18:26:28]

Done.

+  // Possibly clear native focus.

[dmazzoni, 2016/11/22 18:11:42]

Is this necessary? Won't it fix itself when the new frame is retrieved?

[David Tseng, 2016/11/22 18:26:28]

Navigation could still occur before then, but likely not for long before the
reserialized frame comes back.
I removed it.

+  var focusedNodeInfo = GetFocusNative(DESKTOP_TREE_ID);
+  if (focusedNodeInfo && focusedNodeInfo.treeId == id)
+    automationUtil.focusedNode = null;
+  automationInternal.enableFrame(id);

[dmazzoni, 2016/11/22 18:11:42]

Does calling enableFrame() force it to reset?

I think we should either add a comment to enableFrame saying that
it must reset (otherwise we could accidentally try to optimize away
redundant calls to enableFrame), or else we should add a separate
resetFrame call.

[David Tseng, 2016/11/22 18:26:28]

Let's rename this to enableOrResetFrame (in another cl). That's how it's been
used and it's automation only (tree only mode).

+});
+
 var binding = automation.generate();
 // Add additional accessibility bindings not specified in the automation IDL.
 // Accessibility and automation share some APIs (see
 // ui/accessibility/ax_enums.idl).
 forEach(schema, function(k, v) {
   binding[k] = v;
 });
 
 exports.$set('binding', binding);