DevTools: Show HTML tree (#32655)

* feat: watch root node

Signed-off-by: eri <eri@inventati.org>

* reafactor: divide inspector in components

Signed-off-by: eri <eri@inventati.org>

* feat: add css properties actor

Signed-off-by: eri <eri@inventati.org>

* feat: accesibility actor

Signed-off-by: eri <eri@inventati.org>

* feat: layout actor

Signed-off-by: eri <eri@inventati.org>

* feat: network parent and refactor

Signed-off-by: eri <eri@inventati.org>

* feat: progress on the inspector messages

Signed-off-by: eri <eri@inventati.org>

* feat: more progress on inspector

Signed-off-by: eri <eri@inventati.org>

* feat: try to fix nodes showing

Signed-off-by: eri <eri@inventati.org>

* feat: initial dom tree

Signed-off-by: eri <eri@inventati.org>

* feat: some more messages

Signed-off-by: eri <eri@inventati.org>

* feat: clean and add documentation

Signed-off-by: eri <eri@inventati.org>

* refactor: add more docs and clean

Signed-off-by: eri <eri@inventati.org>

* fix: restore deleted node attributes field

Signed-off-by: eri <eri@inventati.org>

* Apply suggestions from code review

Fix a few nits in comments

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

---------

Signed-off-by: eri <eri@inventati.org>
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>

components/devtools/actors/root.rs

@@ -52,7 +52,6 @@ struct GetRootReply {
 #[derive(Serialize)]
 struct ListTabsReply {
     from: String,
-    selected: u32,
     tabs: Vec<TabDescriptorActorMsg>,
 }
 
@@ -182,7 +181,6 @@ impl Actor for RootActor {
             "listTabs" => {
                 let actor = ListTabsReply {
                     from: "root".to_owned(),
-                    selected: 0,
                     tabs: self
                         .tabs
                         .iter()