[headless] AddWindowTreeClient

headless/lib/headless_devtools_client_browsertest.cc

Index: headless/lib/headless_devtools_client_browsertest.cc
diff --git a/headless/lib/headless_devtools_client_browsertest.cc b/headless/lib/headless_devtools_client_browsertest.cc
index 5c3807f4835463da5924214d043d9f80448584ee..095a746884c713af418b03d5009f4894f2ac3993 100644
--- a/headless/lib/headless_devtools_client_browsertest.cc
+++ b/headless/lib/headless_devtools_client_browsertest.cc
@@ -49,10 +49,11 @@ class HeadlessDevToolsClientTest : public HeadlessBrowserTest,
 
     web_contents_->GetDevToolsTarget()->DetachClient(devtools_client_.get());
     web_contents_->RemoveObserver(this);
+    web_contents_->Close();
     web_contents_ = nullptr;
   }
 
-  std::unique_ptr<HeadlessWebContents> web_contents_;
+  HeadlessWebContents* web_contents_;
   std::unique_ptr<HeadlessDevToolsClient> devtools_client_;
 };