Add CSS agent for various window/widget/view attributes in devtools

ash/common/devtools/ash_devtools_dom_agent.h

Index: ash/common/devtools/ash_devtools_dom_agent.h
diff --git a/ash/common/devtools/ash_devtools_dom_agent.h b/ash/common/devtools/ash_devtools_dom_agent.h
index 97cae3050eb1eb042de35b0c9133e75b25403feb..dab35b99117368722962a06bf867a7182f1c20cb 100644
--- a/ash/common/devtools/ash_devtools_dom_agent.h
+++ b/ash/common/devtools/ash_devtools_dom_agent.h
@@ -10,6 +10,8 @@
 #include "base/compiler_specific.h"
 #include "components/ui_devtools/DOM.h"
 #include "components/ui_devtools/devtools_base_agent.h"
+#include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
 
 namespace ash {
 namespace devtools {
@@ -34,7 +36,15 @@ class ASH_EXPORT AshDevToolsDOMAgent
                            const TreeChangeParams& params) override;
   void OnWindowStackingChanged(WmWindow* window) override;
 
+  WmWindow* GetWindowFromNodeId(int nodeId);
+  views::Widget* GetWidgetFromNodeId(int nodeId);
+  views::View* GetViewFromNodeId(int nodeId);
+
  private:
+  std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildTreeForView(
+      views::View* view);
+  std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildTreeForRootWidget(
+      views::Widget* widget);
   std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildTreeForWindow(
       WmWindow* window);
   std::unique_ptr<ui::devtools::protocol::DOM::Node> BuildInitialTree();
@@ -49,6 +59,10 @@ class ASH_EXPORT AshDevToolsDOMAgent
   using WindowToNodeIdMap = std::unordered_map<WmWindow*, int>;
   WindowToNodeIdMap window_to_node_id_map_;
 
+  std::unordered_map<int, WmWindow*> node_id_to_window_map_;
+  std::unordered_map<int, views::Widget*> node_id_to_widget_map_;
+  std::unordered_map<int, views::View*> node_id_to_view_map_;
+
   DISALLOW_COPY_AND_ASSIGN(AshDevToolsDOMAgent);
 };