Fix crashes in AutomationInternalCustomBindings due to no v8 context.

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 844fd87dd09790dbc38ce9615333ee5698240fdd..3a620c89d4946091ff07a0c49c8899ca0bcbd6ed 100644
--- a/chrome/renderer/extensions/automation_internal_custom_bindings.cc
+++ b/chrome/renderer/extensions/automation_internal_custom_bindings.cc
@@ -136,8 +136,14 @@ AutomationInternalCustomBindings::AutomationInternalCustomBindings(
 AutomationInternalCustomBindings::~AutomationInternalCustomBindings() {
   if (message_filter_)

[David Tseng, 2015/11/03 18:37:44]

Perhaps this class needs to override Invalidate (and do this teardown logic
there)?

[dmazzoni, 2015/11/06 22:49:58]

Good catch. Done, that seems to work.

     message_filter_->Detach();
-  STLDeleteContainerPairSecondPointers(tree_id_to_tree_cache_map_.begin(),
-                                       tree_id_to_tree_cache_map_.end());
+
+  // Delete the TreeCaches quickly by first clearing their delegates so
+  // we don't get a callback for every node being deleted.
+  for (auto iter : tree_id_to_tree_cache_map_) {
+    TreeCache* cache = iter.second;
+    cache->tree.SetDelegate(nullptr);
+    delete cache;
+  }
 }
 
 void AutomationInternalCustomBindings::OnMessageReceived(
@@ -628,6 +634,9 @@ void AutomationInternalCustomBindings::SendTreeChangeEvent(
   if (!is_active_profile_)
     return;
 
+  if (!GetIsolate() || !context())

[David Tseng, 2015/11/03 18:37:44]

Do you need to do this if teardown occurs in Invalidate?

[dmazzoni, 2015/11/06 22:49:58]

Probably not.

+    return;
+
   auto iter = axtree_to_tree_cache_map_.find(tree);
   if (iter == axtree_to_tree_cache_map_.end())
     return;