Reimplement automation API on top of C++-backed AXTree.

chrome/browser/extensions/api/automation_internal/automation_event_router.cc

 // Copyright 2015 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.
 
 #include "chrome/browser/extensions/api/automation_internal/automation_event_router.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
@@ skipping 44 matching lines @@
 void AutomationEventRouter::DispatchAccessibilityEvent(
     const ExtensionMsg_AccessibilityEventParams& params) {
   for (const auto& listener : listeners_) {
     if (!listener.desktop &&
         listener.tree_ids.find(params.tree_id) == listener.tree_ids.end()) {
       continue;
     }
 
     content::RenderProcessHost* rph =
         content::RenderProcessHost::FromID(listener.process_id);
-    rph->Send(new ExtensionMsg_AccessibilityEvent(listener.routing_id, params));
+    if (rph) {

[aboxhall, 2015/06/11 20:32:42]

Could you add a comment as to why rph may not exist?

[dmazzoni, 2015/06/12 17:51:36]

I was wrong. It should always exist because we explicitly catch
NOTIFICATION_RENDERER_PROCESS_TERMINATED below.

I changed this to a CHECK.

+      rph->Send(new ExtensionMsg_AccessibilityEvent(listener.routing_id,
+                                                    params));
+    }
   }
 }
 
 void AutomationEventRouter::DispatchTreeDestroyedEvent(
     int tree_id,
     content::BrowserContext* browser_context) {
   std::string event_name(
       api::automation_internal::OnAccessibilityTreeDestroyed::kEventName);
   scoped_ptr<base::ListValue> args(
       api::automation_internal::OnAccessibilityTreeDestroyed::Create(tree_id));
@@ skipping 54 matching lines @@
   int process_id = rph->GetID();
   std::remove_if(
       listeners_.begin(),
       listeners_.end(),
       [process_id](AutomationListener& item) {
         return item.process_id = process_id;
       });
 }
 
 }  // namespace extensions