Add ash devtools client

ash/common/wm_shell.cc

Index: ash/common/wm_shell.cc
diff --git a/ash/common/wm_shell.cc b/ash/common/wm_shell.cc
index d5c49e3bfa97db1d102250991fca9123ff40d62f..569844003573302d3868a4d1bf8fde9dc3b8fd9b 100644
--- a/ash/common/wm_shell.cc
+++ b/ash/common/wm_shell.cc
@@ -9,6 +9,7 @@
 #include "ash/common/accelerators/accelerator_controller.h"
 #include "ash/common/accelerators/ash_focus_manager_factory.h"
 #include "ash/common/accessibility_delegate.h"
+#include "ash/common/devtools/devtools_client_dom.h"
 #include "ash/common/focus_cycler.h"
 #include "ash/common/keyboard/keyboard_ui.h"
 #include "ash/common/new_window_delegate.h"
@@ -87,6 +88,17 @@ void WmShell::Initialize(const scoped_refptr<base::SequencedWorkerPool>& pool) {
   new_window_delegate_.reset(delegate_->CreateNewWindowDelegate());
 
   wallpaper_controller_.reset(new WallpaperController(blocking_pool_));
+
+  // Start devtools server
+  devtools_server_ = ui::devtools::UiDevToolsServer::Create();
+  if (devtools_server_) {
+    std::unique_ptr<ui::devtools::protocol::DOM::Backend> backend(
+        new ui::devtools::AshDevToolsClientDOM(this));
+    std::unique_ptr<ui::devtools::UiDevToolsClient> devtools_client(
+        new ui::devtools::UiDevToolsClient("Ash", devtools_server_.get()));
+    devtools_client->AddDOMBackend(std::move(backend));
+    devtools_server_->AttachClient(std::move(devtools_client));
+  }
 }
 
 void WmShell::Shutdown() {