Push updates to inspector when windows are added, destroyed or reorganized

ash/common/devtools/ash_devtools_dom_agent.cc

Index: ash/common/devtools/ash_devtools_dom_agent.cc
diff --git a/ash/common/devtools/ash_devtools_dom_agent.cc b/ash/common/devtools/ash_devtools_dom_agent.cc
index 366ab9b7e6855422cb13cb76165ba3b2d619839a..8640892d34058c41bf04db7ee5f345c1f347a7d3 100644
--- a/ash/common/devtools/ash_devtools_dom_agent.cc
+++ b/ash/common/devtools/ash_devtools_dom_agent.cc
@@ -14,12 +14,12 @@ namespace devtools {
 
 namespace {
 using namespace ui::devtools::protocol;
+DOM::NodeId node_ids = 1;
 
 std::unique_ptr<DOM::Node> BuildNode(
     const std::string& name,
     std::unique_ptr<Array<std::string>> attributes,
     std::unique_ptr<Array<DOM::Node>> children) {
-  static DOM::NodeId node_ids = 0;
   constexpr int kDomElementNodeType = 1;
   std::unique_ptr<DOM::Node> node = DOM::Node::create()
                                         .setNodeId(node_ids++)
@@ -71,15 +71,13 @@ std::unique_ptr<DOM::Node> BuildTreeForRootWidget(views::Widget* widget) {
   return BuildNode("Widget", GetAttributes(widget), std::move(children));
 }
 
-std::unique_ptr<DOM::Node> BuildTreeForWindow(ash::WmWindow* window) {
-  std::unique_ptr<Array<DOM::Node>> children = Array<DOM::Node>::create();
-  for (ash::WmWindow* child : window->GetChildren()) {
-    children->addItem(BuildTreeForWindow(child));
-    views::Widget* widget = child->GetInternalWidget();
-    if (widget)
-      children->addItem(BuildTreeForRootWidget(widget));
-  }
-  return BuildNode("Window", GetAttributes(window), std::move(children));
+WmWindow* FindPreviousSibling(WmWindow* window) {
+  std::vector<WmWindow*> siblings = window->GetParent()->GetChildren();
+  std::vector<WmWindow*>::iterator it =
+      std::find(siblings.begin(), siblings.end(), window);
+  DCHECK(it != siblings.end());
+  // If this is the first child of its parent, the previous sibling is null
+  return it == siblings.begin() ? nullptr : *std::prev(it);
 }
 
 }  // namespace
@@ -88,7 +86,63 @@ AshDevToolsDOMAgent::AshDevToolsDOMAgent(ash::WmShell* shell) : shell_(shell) {
   DCHECK(shell_);
 }
 
-AshDevToolsDOMAgent::~AshDevToolsDOMAgent() {}
+AshDevToolsDOMAgent::~AshDevToolsDOMAgent() {
+  RemoveObserverFromAllWindows();
+}
+
+ui::devtools::protocol::Response AshDevToolsDOMAgent::disable() {
+  Reset();
+  return ui::devtools::protocol::Response::OK();
+}
+
+ui::devtools::protocol::Response AshDevToolsDOMAgent::getDocument(
+    std::unique_ptr<ui::devtools::protocol::DOM::Node>* out_root) {
+  *out_root = BuildInitialTree();
+  return ui::devtools::protocol::Response::OK();
+}
+
+// Need to remove node in OnWindowDestroying because the window parent reference
+// is gone in OnWindowDestroyed
+void AshDevToolsDOMAgent::OnWindowDestroying(WmWindow* window) {
+  RemoveWindowNode(window, window->GetParent());
+}
+
+void AshDevToolsDOMAgent::OnWindowTreeChanged(WmWindow* window,
+                                              const TreeChangeParams& params) {
+  // Only trigger this when window == root window.
+  // Removals are handled on OnWindowDestroying.
+  if (window != window->GetRootWindow() || !params.new_parent)
+    return;
+  // If there is an old_parent + new_parent, then this window is being moved
+  // which requires a remove followed by an add. If only new_parent
+  // exists, then a new window is being created so only add is called.
+  if (params.old_parent)
+    RemoveWindowNode(params.target, params.old_parent);
+  AddWindowNode(params.target);
+}
+
+void AshDevToolsDOMAgent::OnWindowStackingChanged(WmWindow* window) {
+  RemoveWindowNode(window, window->GetParent());
+  AddWindowNode(window);
+}
+
+std::unique_ptr<DOM::Node> AshDevToolsDOMAgent::BuildTreeForWindow(
+    ash::WmWindow* window) {
+  std::unique_ptr<Array<DOM::Node>> children = Array<DOM::Node>::create();
+  for (ash::WmWindow* child : window->GetChildren()) {
+    children->addItem(BuildTreeForWindow(child));
+    views::Widget* widget = child->GetInternalWidget();
+    if (widget)
+      children->addItem(BuildTreeForRootWidget(widget));
+  }
+  std::unique_ptr<ui::devtools::protocol::DOM::Node> node =
+      BuildNode("Window", GetAttributes(window), std::move(children));
+  // Only add as observer if window is not in map
+  if (!window_to_node_id_map_.count(window))
+    window->AddObserver(this);
+  window_to_node_id_map_[window] = node->getNodeId();
+  return node;
+}
 
 std::unique_ptr<ui::devtools::protocol::DOM::Node>
 AshDevToolsDOMAgent::BuildInitialTree() {
@@ -99,18 +153,36 @@ AshDevToolsDOMAgent::BuildInitialTree() {
   return BuildNode("root", nullptr, std::move(children));
 }
 
-ui::devtools::protocol::Response AshDevToolsDOMAgent::enable() {
-  return ui::devtools::protocol::Response::OK();
+void AshDevToolsDOMAgent::AddWindowNode(WmWindow* window) {
+  WmWindow* prev_sibling = FindPreviousSibling(window);
+  frontend()->childNodeInserted(
+      window_to_node_id_map_[window->GetParent()],
+      prev_sibling ? window_to_node_id_map_[prev_sibling] : 0,
+      BuildTreeForWindow(window));
 }
 
-ui::devtools::protocol::Response AshDevToolsDOMAgent::disable() {
-  return ui::devtools::protocol::Response::OK();
+void AshDevToolsDOMAgent::RemoveWindowNode(WmWindow* window,
+                                           WmWindow* old_parent) {
+  window->RemoveObserver(this);
+  WindowToNodeIdMap::iterator it = window_to_node_id_map_.find(window);
+  DCHECK(it != window_to_node_id_map_.end());
+
+  int node_id = it->second;
+  int parent_id = old_parent ? window_to_node_id_map_[old_parent] : 0;
+
+  window_to_node_id_map_.erase(it);
+  frontend()->childNodeRemoved(parent_id, node_id);
 }
 
-ui::devtools::protocol::Response AshDevToolsDOMAgent::getDocument(
-    std::unique_ptr<ui::devtools::protocol::DOM::Node>* out_root) {
-  *out_root = BuildInitialTree();
-  return ui::devtools::protocol::Response::OK();
+void AshDevToolsDOMAgent::RemoveObserverFromAllWindows() {
+  for (auto& pair : window_to_node_id_map_)
+    pair.first->RemoveObserver(this);
+}
+
+void AshDevToolsDOMAgent::Reset() {
+  RemoveObserverFromAllWindows();
+  window_to_node_id_map_.clear();
+  node_ids = 1;
 }
 
 }  // namespace devtools