[DevTools] Only create DevToolsAgentHost for main frame and cross-process subframes.

content/browser/devtools/site_per_process_devtools_browsertest.cc

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/site_per_process_browsertest.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/devtools_agent_host.h"
 #include "content/public/test/content_browser_test_utils.h"
@@ skipping 85 matching lines @@
   TestClient client;
   child_host->AttachClient(&client);
 
   // Load back same-site page into iframe.
   NavigateFrameToURL(root->child_at(0), http_url);
 
   list = DevToolsAgentHost::GetOrCreateAll();
   EXPECT_EQ(1U, list.size());
   EXPECT_EQ(DevToolsAgentHost::TYPE_WEB_CONTENTS, list[0]->GetType());
   EXPECT_EQ(main_url.spec(), list[0]->GetURL().spec());
-  // TODO(dgozman): we should get closed notification here.
-  // See http://crbug.com/464993.
-  EXPECT_FALSE(client.closed());
+  EXPECT_TRUE(client.closed());
   child_host->DetachClient();
   child_host = nullptr;
 }
 
 }  // namespace content