Fix bug where removed (but not deleted) windows are not reflected in the tree properly

ash/common/devtools/ash_devtools_unittest.cc

Index: ash/common/devtools/ash_devtools_unittest.cc
diff --git a/ash/common/devtools/ash_devtools_unittest.cc b/ash/common/devtools/ash_devtools_unittest.cc
index 1a79c07dc2cf5032503b3a7dfaf9103bde2a898a..2bbcacd02aca8105ab80b3e38f491a69974ee184 100644
--- a/ash/common/devtools/ash_devtools_unittest.cc
+++ b/ash/common/devtools/ash_devtools_unittest.cc
@@ -225,6 +225,30 @@ TEST_F(AshDevToolsTest, WindowDestroyedChildNodeRemoved) {
   ExpectChildNodeRemoved(parent_node->getNodeId(), child_node->getNodeId());
 }
 
+TEST_F(AshDevToolsTest, WindowReorganizedChildNodeRearranged) {
+  // Initialize DOMAgent
+  std::unique_ptr<ui::devtools::protocol::DOM::Node> root;
+  dom_agent()->getDocument(&root);
+
+  WmWindow* root_window = WmShell::Get()->GetPrimaryRootWindow();
+  WmWindow* target_window = root_window->GetChildren()[1];
+  WmWindow* child_window = root_window->GetChildren()[0]->GetChildren()[0];
+
+  DOM::Node* root_node = root->getChildren(nullptr)->get(0);
+  DOM::Node* parent_node = root_node->getChildren(nullptr)->get(0);
+  DOM::Node* target_node = root_node->getChildren(nullptr)->get(1);
+  Array<DOM::Node>* target_node_children = target_node->getChildren(nullptr);
+  DOM::Node* sibling_node =
+      target_node_children->get(target_node_children->length() - 1);
+  DOM::Node* child_node = parent_node->getChildren(nullptr)->get(0);
+
+  Compare(target_window, target_node);
+  Compare(child_window, child_node);
+  target_window->AddChild(child_window);
+  ExpectChildNodeRemoved(parent_node->getNodeId(), child_node->getNodeId());
+  ExpectChildNodeInserted(target_node->getNodeId(), sibling_node->getNodeId());
+}
+
 TEST_F(AshDevToolsTest, WindowReorganizedChildNodeRemovedAndInserted) {
   // Initialize DOMAgent
   std::unique_ptr<ui::devtools::protocol::DOM::Node> root;
@@ -244,6 +268,7 @@ TEST_F(AshDevToolsTest, WindowReorganizedChildNodeRemovedAndInserted) {
 
   Compare(target_window, target_node);
   Compare(child_window, child_node);
+  child_window->GetParent()->RemoveChild(child_window);

[sadrul, 2016/11/10 20:25:24]

Why is this necessary?

[Sarmad Hashmi, 2016/11/10 21:00:34]

We know AddChild removes |window| from its old parent. This test simply confirms
that a |window| with no parent (i.e: a removed but not destroyed child) that is
added as a child to another window at a later time still triggers remove/insert
calls.

   target_window->AddChild(child_window);
   ExpectChildNodeRemoved(parent_node->getNodeId(), child_node->getNodeId());
   ExpectChildNodeInserted(target_node->getNodeId(), sibling_node->getNodeId());