One accessibility tree per frame.

chrome/browser/extensions/api/automation/automation_apitest.cc

 // Copyright 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 "base/files/file_path.h"
 #include "base/location.h"
 #include "base/path_service.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 154 matching lines @@
       RunExtensionSubtest("automation/tests/desktop", "initial_focus.html"))
       << message_;
 }
 
 IN_PROC_BROWSER_TEST_F(AutomationApiTest, DesktopFocusWeb) {
   ASSERT_TRUE(
       RunExtensionSubtest("automation/tests/desktop", "focus_web.html"))
       << message_;
 }
 
+IN_PROC_BROWSER_TEST_F(AutomationApiTest, DesktopFocusIframe) {
+  StartEmbeddedTestServer();
+  ASSERT_TRUE(
+      RunExtensionSubtest("automation/tests/desktop", "focus_iframe.html"))
+      << message_;
+}
+
 IN_PROC_BROWSER_TEST_F(AutomationApiTest, DesktopFocusViews) {
   AutomationManagerAura::GetInstance()->Enable(browser()->profile());
   // Trigger the shelf subtree to be computed.
   ash::Shell::GetInstance()->accelerator_controller()->PerformActionIfEnabled(
       ash::FOCUS_SHELF);
 
   ASSERT_TRUE(
       RunExtensionSubtest("automation/tests/desktop", "focus_views.html"))
       << message_;
 }
@@ skipping 61 matching lines @@
 }
 
 IN_PROC_BROWSER_TEST_F(AutomationApiTest, DocumentSelection) {
   StartEmbeddedTestServer();
   ASSERT_TRUE(
       RunExtensionSubtest("automation/tests/tabs", "document_selection.html"))
       << message_;
 }
 
 }  // namespace extensions