mash/wm: Fix detecting container windows.

mash/wm/window_manager.cc

Index: mash/wm/window_manager.cc
diff --git a/mash/wm/window_manager.cc b/mash/wm/window_manager.cc
index fcaaea2077287b8768dbf08dc58fdb689daf93b2..f8adfab67deb41c11e9d2cca36ddfe6d28c056a4 100644
--- a/mash/wm/window_manager.cc
+++ b/mash/wm/window_manager.cc
@@ -44,11 +44,17 @@ void WindowManager::Initialize(RootWindowController* root_controller,
   DCHECK(root_controller);
   DCHECK(!root_controller_);
   root_controller_ = root_controller;
-  // The children of the root are considered containers.
-  for (auto container : root_controller_->root()->children()) {
+
+  // Observe all the containers and their child windows.

[sky, 2016/04/22 15:23:42]

Why do you need to observer the child windows?

[sky, 2016/04/22 15:25:40]

Never mind this comment, I just saw your comments in your other patch and get
why you want to observe children. I think it's error prone to have this class
observe two types of windows for different purposes. I would rather you add an
observer specifically for children.

[sadrul, 2016/04/22 16:06:05]

Done (introduced a DisconnectedAppHandler). Change both WindowManager and
DisconnectedAppHandler to become WindowTrackers too, to make it easier to stop
observing during teardown.

+  int count = static_cast<int>(mojom::Container::COUNT);
+  for (int id = 1; id < count; ++id) {

[sky, 2016/04/22 15:23:42]

1 -> ROOT + 1 ?

[sadrul, 2016/04/22 16:06:06]

Done.

+    mus::Window* container = root_controller_->GetWindowForContainer(
+        static_cast<mojom::Container>(id));
     container->AddObserver(this);
-    for (auto child : container->children())
-      child->AddObserver(this);
+    for (auto child : container->children()) {
+      if (!root_controller_->WindowIsContainer(child))
+        child->AddObserver(this);
+    }
   }
 
   // The insets are roughly what is needed by CustomFrameView. The expectation
@@ -111,7 +117,10 @@ mus::Window* WindowManager::NewTopLevelWindow(
   window->SetBounds(CalculateDefaultBounds(window));
 
   mojom::Container container = GetRequestedContainer(window);
-  root_controller_->GetWindowForContainer(container)->AddChild(window);
+  mus::Window* container_window =
+      root_controller_->GetWindowForContainer(container);
+  DCHECK(root_controller_->WindowIsContainer(container_window));
+  container_window->AddChild(window);
 
   if (provide_non_client_frame) {
     NonClientFrameController::Create(root_controller_->GetConnector(), window,
@@ -125,9 +134,12 @@ mus::Window* WindowManager::NewTopLevelWindow(
 
 void WindowManager::OnTreeChanging(const TreeChangeParams& params) {
   DCHECK(root_controller_);
-  if (root_controller_->WindowIsContainer(params.old_parent))
+  if (params.old_parent == params.receiver &&
+      root_controller_->WindowIsContainer(params.old_parent))
     params.target->RemoveObserver(this);
-  else if (root_controller_->WindowIsContainer(params.new_parent))
+
+  if (params.new_parent == params.receiver &&
+      root_controller_->WindowIsContainer(params.new_parent))
     params.target->AddObserver(this);
 }