Deletion/ownership

mojo/services/public/cpp/view_manager/lib/view_tree_node.cc

Index: mojo/services/public/cpp/view_manager/lib/view_tree_node.cc
diff --git a/mojo/services/public/cpp/view_manager/lib/view_tree_node.cc b/mojo/services/public/cpp/view_manager/lib/view_tree_node.cc
index 33d90a9bb6a258382fe6444e34acde6bd13c8a8c..74e88a96bf076d06d9300554ccf12cc258429f97 100644
--- a/mojo/services/public/cpp/view_manager/lib/view_tree_node.cc
+++ b/mojo/services/public/cpp/view_manager/lib/view_tree_node.cc
@@ -90,36 +90,19 @@ void RemoveChildImpl(ViewTreeNode* child, ViewTreeNode::Children* children) {
 ////////////////////////////////////////////////////////////////////////////////
 // ViewTreeNode, public:
 
-ViewTreeNode::ViewTreeNode()
-    : manager_(NULL),
-      id_(-1),
-      owned_by_parent_(true),
-      parent_(NULL) {}
-
-ViewTreeNode::ViewTreeNode(ViewManager* manager)
-    : manager_(manager),
-      id_(ViewManagerPrivate(manager).synchronizer()->CreateViewTreeNode()),
-      owned_by_parent_(true),
-      parent_(NULL) {}
-
-ViewTreeNode::~ViewTreeNode() {
-  while (!children_.empty()) {
-    ViewTreeNode* child = children_.front();
-    if (child->owned_by_parent_) {
-      delete child;
-      // Deleting the child also removes it from our child list.
-      DCHECK(std::find(children_.begin(), children_.end(), child) ==
-             children_.end());
-    } else {
-      RemoveChild(child);
-    }
-  }
-
-  if (parent_)
-    parent_->RemoveChild(this);
+// static
+ViewTreeNode* ViewTreeNode::Create(ViewManager* view_manager) {
+  ViewTreeNode* node = new ViewTreeNode(view_manager);
+  ViewManagerPrivate(view_manager).AddNode(node->id(), node);
+  return node;
+}
 
+void ViewTreeNode::Destroy() {
   if (manager_)
     ViewManagerPrivate(manager_).synchronizer()->DestroyViewTreeNode(id_);
+  while (!children_.empty())
+    children_.front()->Destroy();
+  LocalDestroy();
 }
 
 void ViewTreeNode::AddObserver(ViewTreeNodeObserver* observer) {
@@ -164,8 +147,40 @@ ViewTreeNode* ViewTreeNode::GetChildById(TransportNodeId id) {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// ViewTreeNode, protected:
+
+ViewTreeNode::ViewTreeNode()
+    : manager_(NULL),
+      id_(-1),
+      parent_(NULL) {}
+
+ViewTreeNode::~ViewTreeNode() {
+  FOR_EACH_OBSERVER(
+      ViewTreeNodeObserver,
+      observers_,
+      OnNodeDestroy(this, ViewTreeNodeObserver::DISPOSITION_CHANGING));
+  if (parent_)
+    parent_->LocalRemoveChild(this);
+  FOR_EACH_OBSERVER(
+      ViewTreeNodeObserver,
+      observers_,
+      OnNodeDestroy(this, ViewTreeNodeObserver::DISPOSITION_CHANGED));
+  if (manager_)
+    ViewManagerPrivate(manager_).RemoveNode(id_);
+}
+
+////////////////////////////////////////////////////////////////////////////////
 // ViewTreeNode, private:
 
+ViewTreeNode::ViewTreeNode(ViewManager* manager)
+    : manager_(manager),
+      id_(ViewManagerPrivate(manager).synchronizer()->CreateViewTreeNode()),
+      parent_(NULL) {}
+
+void ViewTreeNode::LocalDestroy() {
+  delete this;
+}
+
 void ViewTreeNode::LocalAddChild(ViewTreeNode* child) {
   ScopedTreeNotifier notifier(child, child->parent(), this);
   if (child->parent())