content/renderer/accessibility/render_accessibility_impl_browsertest.cc - chromium/src - Git at Google

 // Copyright (c) 2012 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 <tuple>

 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "content/common/accessibility_messages.h"
 #include "content/common/frame_messages.h"
 #include "content/common/site_isolation_policy.h"
 #include "content/common/view_message_enums.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/test/render_view_test.h"
 #include "content/renderer/accessibility/render_accessibility_impl.h"
 #include "content/renderer/render_frame_impl.h"
 #include "content/renderer/render_view_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebSize.h"
 #include "third_party/WebKit/public/web/WebAXObject.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "ui/accessibility/ax_node_data.h"

 using blink::WebAXObject;
 using blink::WebDocument;

 namespace content {

 class TestRenderAccessibilityImpl : public RenderAccessibilityImpl {
  public:
   explicit TestRenderAccessibilityImpl(RenderFrameImpl* render_frame)
     : RenderAccessibilityImpl(render_frame) {
   }

   void SendPendingAccessibilityEvents() {
     RenderAccessibilityImpl::SendPendingAccessibilityEvents();
   }
 };

 class RenderAccessibilityImplTest : public RenderViewTest {
  public:
   RenderAccessibilityImplTest() {}

   RenderViewImpl* view() {
     return static_cast<RenderViewImpl*>(view_);
   }

   RenderFrameImpl* frame() {
     return static_cast<RenderFrameImpl*>(view()->GetMainRenderFrame());
   }

   void SetUp() override {
     RenderViewTest::SetUp();
     sink_ = &render_thread_->sink();
   }

   void TearDown() override {
 #if defined(LEAK_SANITIZER)
      // Do this before shutting down V8 in RenderViewTest::TearDown().
      // http://crbug.com/328552
      __lsan_do_leak_check();
 #endif
      RenderViewTest::TearDown();
   }

   void SetMode(AccessibilityMode mode) {
     frame()->OnSetAccessibilityMode(mode);
   }

   void GetAllAccEvents(
       std::vector<AccessibilityHostMsg_EventParams>* param_list) {
     const IPC::Message* message =
         sink_->GetUniqueMessageMatching(AccessibilityHostMsg_Events::ID);
     ASSERT_TRUE(message);
     std::tuple<std::vector<AccessibilityHostMsg_EventParams>, int> param;
     AccessibilityHostMsg_Events::Read(message, &param);
     *param_list = std::get<0>(param);
   }

   void GetLastAccEvent(
       AccessibilityHostMsg_EventParams* params) {
     std::vector<AccessibilityHostMsg_EventParams> param_list;
     GetAllAccEvents(&param_list);
     ASSERT_GE(param_list.size(), 1U);
     *params = param_list[0];
   }

   int CountAccessibilityNodesSentToBrowser() {
     AccessibilityHostMsg_EventParams event;
     GetLastAccEvent(&event);
     return event.update.nodes.size();
   }

  protected:
   IPC::TestSink* sink_;

   DISALLOW_COPY_AND_ASSIGN(RenderAccessibilityImplTest);

 };

 TEST_F(RenderAccessibilityImplTest, SendFullAccessibilityTreeOnReload) {
   // The job of RenderAccessibilityImpl is to serialize the
   // accessibility tree built by WebKit and send it to the browser.
   // When the accessibility tree changes, it tries to send only
   // the nodes that actually changed or were reparented. This test
   // ensures that the messages sent are correct in cases when a page
   // reloads, and that internal state is properly garbage-collected.
   std::string html =
       "<body>"
       "  <div role='group' id='A'>"
       "    <div role='group' id='A1'></div>"
       "    <div role='group' id='A2'></div>"
       "  </div>"
       "</body>";
   LoadHTML(html.c_str());

   // Creating a RenderAccessibilityImpl should sent the tree to the browser.
   std::unique_ptr<TestRenderAccessibilityImpl> accessibility(
       new TestRenderAccessibilityImpl(frame()));
   accessibility->SendPendingAccessibilityEvents();
   EXPECT_EQ(4, CountAccessibilityNodesSentToBrowser());

   // If we post another event but the tree doesn't change,
   // we should only send 1 node to the browser.
   sink_->ClearMessages();
   WebDocument document = view()->GetWebView()->mainFrame()->document();
   WebAXObject root_obj = document.accessibilityObject();
   accessibility->HandleAXEvent(
       root_obj,
       ui::AX_EVENT_LAYOUT_COMPLETE);
   accessibility->SendPendingAccessibilityEvents();
   EXPECT_EQ(1, CountAccessibilityNodesSentToBrowser());
   {
     // Make sure it's the root object that was updated.
     AccessibilityHostMsg_EventParams event;
     GetLastAccEvent(&event);
     EXPECT_EQ(root_obj.axID(), event.update.nodes[0].id);
   }

   // If we reload the page and send a event, we should send
   // all 4 nodes to the browser. Also double-check that we didn't
   // leak any of the old BrowserTreeNodes.
   LoadHTML(html.c_str());
   document = view()->GetWebView()->mainFrame()->document();
   root_obj = document.accessibilityObject();
   sink_->ClearMessages();
   accessibility->HandleAXEvent(
       root_obj,
       ui::AX_EVENT_LAYOUT_COMPLETE);
   accessibility->SendPendingAccessibilityEvents();
   EXPECT_EQ(4, CountAccessibilityNodesSentToBrowser());

   // Even if the first event is sent on an element other than
   // the root, the whole tree should be updated because we know
   // the browser doesn't have the root element.
   LoadHTML(html.c_str());
   document = view()->GetWebView()->mainFrame()->document();
   root_obj = document.accessibilityObject();
   sink_->ClearMessages();
   const WebAXObject& first_child = root_obj.childAt(0);
   accessibility->HandleAXEvent(
       first_child,
       ui::AX_EVENT_LIVE_REGION_CHANGED);
   accessibility->SendPendingAccessibilityEvents();
   EXPECT_EQ(4, CountAccessibilityNodesSentToBrowser());
 }

 TEST_F(RenderAccessibilityImplTest, HideAccessibilityObject) {
   // Test RenderAccessibilityImpl and make sure it sends the
   // proper event to the browser when an object in the tree
   // is hidden, but its children are not.
   std::string html =
       "<body>"
       "  <div role='group' id='A'>"
       "    <div role='group' id='B'>"
       "      <div role='group' id='C' style='visibility:visible'>"
       "      </div>"
       "    </div>"
       "  </div>"
       "</body>";
   LoadHTML(html.c_str());

   std::unique_ptr<TestRenderAccessibilityImpl> accessibility(
       new TestRenderAccessibilityImpl(frame()));
   accessibility->SendPendingAccessibilityEvents();
   EXPECT_EQ(4, CountAccessibilityNodesSentToBrowser());

   WebDocument document = view()->GetWebView()->mainFrame()->document();
   WebAXObject root_obj = document.accessibilityObject();
   WebAXObject node_a = root_obj.childAt(0);
   WebAXObject node_b = node_a.childAt(0);
   WebAXObject node_c = node_b.childAt(0);

   // Hide node 'B' ('C' stays visible).
   ExecuteJavaScriptForTests(
       "document.getElementById('B').style.visibility = 'hidden';");
   // Force layout now.
   ExecuteJavaScriptForTests("document.getElementById('B').offsetLeft;");

   // Send a childrenChanged on 'A'.
   sink_->ClearMessages();
   accessibility->HandleAXEvent(
       node_a,
       ui::AX_EVENT_CHILDREN_CHANGED);

   accessibility->SendPendingAccessibilityEvents();
   AccessibilityHostMsg_EventParams event;
   GetLastAccEvent(&event);
   ASSERT_EQ(2U, event.update.nodes.size());

   // RenderAccessibilityImpl notices that 'C' is being reparented,
   // so it clears the subtree rooted at 'A', then updates 'A' and then 'C'.
   EXPECT_EQ(node_a.axID(), event.update.node_id_to_clear);
   EXPECT_EQ(node_a.axID(), event.update.nodes[0].id);
   EXPECT_EQ(node_c.axID(), event.update.nodes[1].id);
   EXPECT_EQ(2, CountAccessibilityNodesSentToBrowser());
 }

 TEST_F(RenderAccessibilityImplTest, ShowAccessibilityObject) {
   // Test RenderAccessibilityImpl and make sure it sends the
   // proper event to the browser when an object in the tree
   // is shown, causing its own already-visible children to be
   // reparented to it.
   std::string html =
       "<body>"
       "  <div role='group' id='A'>"
       "    <div role='group' id='B' style='visibility:hidden'>"
       "      <div role='group' id='C' style='visibility:visible'>"
       "      </div>"
       "    </div>"
       "  </div>"
       "</body>";
   LoadHTML(html.c_str());

   std::unique_ptr<TestRenderAccessibilityImpl> accessibility(
       new TestRenderAccessibilityImpl(frame()));
   accessibility->SendPendingAccessibilityEvents();
   EXPECT_EQ(3, CountAccessibilityNodesSentToBrowser());

   // Show node 'B', then send a childrenChanged on 'A'.
   ExecuteJavaScriptForTests(
       "document.getElementById('B').style.visibility = 'visible';");
   ExecuteJavaScriptForTests("document.getElementById('B').offsetLeft;");

   sink_->ClearMessages();
   WebDocument document = view()->GetWebView()->mainFrame()->document();
   WebAXObject root_obj = document.accessibilityObject();
   WebAXObject node_a = root_obj.childAt(0);
   WebAXObject node_b = node_a.childAt(0);
   WebAXObject node_c = node_b.childAt(0);

   accessibility->HandleAXEvent(
       node_a,
       ui::AX_EVENT_CHILDREN_CHANGED);

   accessibility->SendPendingAccessibilityEvents();
   AccessibilityHostMsg_EventParams event;
   GetLastAccEvent(&event);

   ASSERT_EQ(3U, event.update.nodes.size());
   EXPECT_EQ(node_a.axID(), event.update.node_id_to_clear);
   EXPECT_EQ(node_a.axID(), event.update.nodes[0].id);
   EXPECT_EQ(node_b.axID(), event.update.nodes[1].id);
   EXPECT_EQ(node_c.axID(), event.update.nodes[2].id);
   EXPECT_EQ(3, CountAccessibilityNodesSentToBrowser());
 }

 TEST_F(RenderAccessibilityImplTest, DetachAccessibilityObject) {
   // Test RenderAccessibilityImpl and make sure it sends the
   // proper event to the browser when an object in the tree
   // is detached, but its children are not. This can happen when
   // a layout occurs and an anonymous render block is no longer needed.
   std::string html =
       "<body aria-label='Body'>"
       "<span>1</span><span style='display:block'>2</span>"
       "</body>";
   LoadHTML(html.c_str());

   std::unique_ptr<TestRenderAccessibilityImpl> accessibility(
       new TestRenderAccessibilityImpl(frame()));
   accessibility->SendPendingAccessibilityEvents();
   EXPECT_EQ(7, CountAccessibilityNodesSentToBrowser());

   // Initially, the accessibility tree looks like this:
   //
   //   Document
   //   +--Body
   //      +--Anonymous Block
   //         +--Static Text "1"
   //            +--Inline Text Box "1"
   //      +--Static Text "2"
   //         +--Inline Text Box "2"
   WebDocument document = view()->GetWebView()->mainFrame()->document();
   WebAXObject root_obj = document.accessibilityObject();
   WebAXObject body = root_obj.childAt(0);
   WebAXObject anonymous_block = body.childAt(0);
   WebAXObject text_1 = anonymous_block.childAt(0);
   WebAXObject text_2 = body.childAt(1);

   // Change the display of the second 'span' back to inline, which causes the
   // anonymous block to be destroyed.
   ExecuteJavaScriptForTests(
       "document.querySelectorAll('span')[1].style.display = 'inline';");
   // Force layout now.
   ExecuteJavaScriptForTests("document.body.offsetLeft;");

   // Send a childrenChanged on the body.
   sink_->ClearMessages();
   accessibility->HandleAXEvent(
       body,
       ui::AX_EVENT_CHILDREN_CHANGED);

   accessibility->SendPendingAccessibilityEvents();

   // Afterwards, the accessibility tree looks like this:
   //
   //   Document
   //   +--Body
   //      +--Static Text "1"
   //         +--Inline Text Box "1"
   //      +--Static Text "2"
   //         +--Inline Text Box "2"
   //
   // We just assert that there are now four nodes in the
   // accessibility tree and that only three nodes needed
   // to be updated (the body, the static text 1, and
   // the static text 2).

   AccessibilityHostMsg_EventParams event;
   GetLastAccEvent(&event);
   ASSERT_EQ(5U, event.update.nodes.size());

   EXPECT_EQ(body.axID(), event.update.nodes[0].id);
   EXPECT_EQ(text_1.axID(), event.update.nodes[1].id);
   // The third event is to update text_2, but its id changes
   // so we don't have a test expectation for it.
 }

 }  // namespace content
	// Copyright (c) 2012 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 <tuple>

	#include "base/macros.h"
	#include "base/strings/utf_string_conversions.h"
	#include "base/time/time.h"
	#include "build/build_config.h"
	#include "content/common/accessibility_messages.h"
	#include "content/common/frame_messages.h"
	#include "content/common/site_isolation_policy.h"
	#include "content/common/view_message_enums.h"
	#include "content/public/common/content_switches.h"
	#include "content/public/test/render_view_test.h"
	#include "content/renderer/accessibility/render_accessibility_impl.h"
	#include "content/renderer/render_frame_impl.h"
	#include "content/renderer/render_view_impl.h"
	#include "testing/gtest/include/gtest/gtest.h"
	#include "third_party/WebKit/public/platform/WebSize.h"
	#include "third_party/WebKit/public/web/WebAXObject.h"
	#include "third_party/WebKit/public/web/WebDocument.h"
	#include "third_party/WebKit/public/web/WebView.h"
	#include "ui/accessibility/ax_node_data.h"

	using blink::WebAXObject;
	using blink::WebDocument;

	namespace content {

	class TestRenderAccessibilityImpl : public RenderAccessibilityImpl {
	public:
	explicit TestRenderAccessibilityImpl(RenderFrameImpl* render_frame)
	: RenderAccessibilityImpl(render_frame) {
	}

	void SendPendingAccessibilityEvents() {
	RenderAccessibilityImpl::SendPendingAccessibilityEvents();
	}
	};

	class RenderAccessibilityImplTest : public RenderViewTest {
	public:
	RenderAccessibilityImplTest() {}

	RenderViewImpl* view() {
	return static_cast<RenderViewImpl*>(view_);
	}

	RenderFrameImpl* frame() {
	return static_cast<RenderFrameImpl*>(view()->GetMainRenderFrame());
	}

	void SetUp() override {
	RenderViewTest::SetUp();
	sink_ = &render_thread_->sink();
	}

	void TearDown() override {
	#if defined(LEAK_SANITIZER)
	// Do this before shutting down V8 in RenderViewTest::TearDown().
	// http://crbug.com/328552
	__lsan_do_leak_check();
	#endif
	RenderViewTest::TearDown();
	}

	void SetMode(AccessibilityMode mode) {
	frame()->OnSetAccessibilityMode(mode);
	}

	void GetAllAccEvents(
	std::vector<AccessibilityHostMsg_EventParams>* param_list) {
	const IPC::Message* message =
	sink_->GetUniqueMessageMatching(AccessibilityHostMsg_Events::ID);
	ASSERT_TRUE(message);
	std::tuple<std::vector<AccessibilityHostMsg_EventParams>, int> param;
	AccessibilityHostMsg_Events::Read(message, &param);
	*param_list = std::get<0>(param);
	}

	void GetLastAccEvent(
	AccessibilityHostMsg_EventParams* params) {
	std::vector<AccessibilityHostMsg_EventParams> param_list;
	GetAllAccEvents(&param_list);
	ASSERT_GE(param_list.size(), 1U);
	*params = param_list[0];
	}

	int CountAccessibilityNodesSentToBrowser() {
	AccessibilityHostMsg_EventParams event;
	GetLastAccEvent(&event);
	return event.update.nodes.size();
	}

	protected:
	IPC::TestSink* sink_;

	DISALLOW_COPY_AND_ASSIGN(RenderAccessibilityImplTest);

	};

	TEST_F(RenderAccessibilityImplTest, SendFullAccessibilityTreeOnReload) {
	// The job of RenderAccessibilityImpl is to serialize the
	// accessibility tree built by WebKit and send it to the browser.
	// When the accessibility tree changes, it tries to send only
	// the nodes that actually changed or were reparented. This test
	// ensures that the messages sent are correct in cases when a page
	// reloads, and that internal state is properly garbage-collected.
	std::string html =
	"<body>"
	" <div role='group' id='A'>"
	" <div role='group' id='A1'></div>"
	" <div role='group' id='A2'></div>"
	" </div>"
	"</body>";
	LoadHTML(html.c_str());

	// Creating a RenderAccessibilityImpl should sent the tree to the browser.
	std::unique_ptr<TestRenderAccessibilityImpl> accessibility(
	new TestRenderAccessibilityImpl(frame()));
	accessibility->SendPendingAccessibilityEvents();
	EXPECT_EQ(4, CountAccessibilityNodesSentToBrowser());

	// If we post another event but the tree doesn't change,
	// we should only send 1 node to the browser.
	sink_->ClearMessages();
	WebDocument document = view()->GetWebView()->mainFrame()->document();
	WebAXObject root_obj = document.accessibilityObject();
	accessibility->HandleAXEvent(
	root_obj,
	ui::AX_EVENT_LAYOUT_COMPLETE);
	accessibility->SendPendingAccessibilityEvents();
	EXPECT_EQ(1, CountAccessibilityNodesSentToBrowser());
	{
	// Make sure it's the root object that was updated.
	AccessibilityHostMsg_EventParams event;
	GetLastAccEvent(&event);
	EXPECT_EQ(root_obj.axID(), event.update.nodes[0].id);
	}

	// If we reload the page and send a event, we should send
	// all 4 nodes to the browser. Also double-check that we didn't
	// leak any of the old BrowserTreeNodes.
	LoadHTML(html.c_str());
	document = view()->GetWebView()->mainFrame()->document();
	root_obj = document.accessibilityObject();
	sink_->ClearMessages();
	accessibility->HandleAXEvent(
	root_obj,
	ui::AX_EVENT_LAYOUT_COMPLETE);
	accessibility->SendPendingAccessibilityEvents();
	EXPECT_EQ(4, CountAccessibilityNodesSentToBrowser());

	// Even if the first event is sent on an element other than
	// the root, the whole tree should be updated because we know
	// the browser doesn't have the root element.
	LoadHTML(html.c_str());
	document = view()->GetWebView()->mainFrame()->document();
	root_obj = document.accessibilityObject();
	sink_->ClearMessages();
	const WebAXObject& first_child = root_obj.childAt(0);
	accessibility->HandleAXEvent(
	first_child,
	ui::AX_EVENT_LIVE_REGION_CHANGED);
	accessibility->SendPendingAccessibilityEvents();
	EXPECT_EQ(4, CountAccessibilityNodesSentToBrowser());
	}

	TEST_F(RenderAccessibilityImplTest, HideAccessibilityObject) {
	// Test RenderAccessibilityImpl and make sure it sends the
	// proper event to the browser when an object in the tree
	// is hidden, but its children are not.
	std::string html =
	"<body>"
	" <div role='group' id='A'>"
	" <div role='group' id='B'>"
	" <div role='group' id='C' style='visibility:visible'>"
	" </div>"
	" </div>"
	" </div>"
	"</body>";
	LoadHTML(html.c_str());

	std::unique_ptr<TestRenderAccessibilityImpl> accessibility(
	new TestRenderAccessibilityImpl(frame()));
	accessibility->SendPendingAccessibilityEvents();
	EXPECT_EQ(4, CountAccessibilityNodesSentToBrowser());

	WebDocument document = view()->GetWebView()->mainFrame()->document();
	WebAXObject root_obj = document.accessibilityObject();
	WebAXObject node_a = root_obj.childAt(0);
	WebAXObject node_b = node_a.childAt(0);
	WebAXObject node_c = node_b.childAt(0);

	// Hide node 'B' ('C' stays visible).
	ExecuteJavaScriptForTests(
	"document.getElementById('B').style.visibility = 'hidden';");
	// Force layout now.
	ExecuteJavaScriptForTests("document.getElementById('B').offsetLeft;");

	// Send a childrenChanged on 'A'.
	sink_->ClearMessages();
	accessibility->HandleAXEvent(
	node_a,
	ui::AX_EVENT_CHILDREN_CHANGED);

	accessibility->SendPendingAccessibilityEvents();
	AccessibilityHostMsg_EventParams event;
	GetLastAccEvent(&event);
	ASSERT_EQ(2U, event.update.nodes.size());

	// RenderAccessibilityImpl notices that 'C' is being reparented,
	// so it clears the subtree rooted at 'A', then updates 'A' and then 'C'.
	EXPECT_EQ(node_a.axID(), event.update.node_id_to_clear);
	EXPECT_EQ(node_a.axID(), event.update.nodes[0].id);
	EXPECT_EQ(node_c.axID(), event.update.nodes[1].id);
	EXPECT_EQ(2, CountAccessibilityNodesSentToBrowser());
	}

	TEST_F(RenderAccessibilityImplTest, ShowAccessibilityObject) {
	// Test RenderAccessibilityImpl and make sure it sends the
	// proper event to the browser when an object in the tree
	// is shown, causing its own already-visible children to be
	// reparented to it.
	std::string html =
	"<body>"
	" <div role='group' id='A'>"
	" <div role='group' id='B' style='visibility:hidden'>"
	" <div role='group' id='C' style='visibility:visible'>"
	" </div>"
	" </div>"
	" </div>"
	"</body>";
	LoadHTML(html.c_str());

	std::unique_ptr<TestRenderAccessibilityImpl> accessibility(
	new TestRenderAccessibilityImpl(frame()));
	accessibility->SendPendingAccessibilityEvents();
	EXPECT_EQ(3, CountAccessibilityNodesSentToBrowser());

	// Show node 'B', then send a childrenChanged on 'A'.
	ExecuteJavaScriptForTests(
	"document.getElementById('B').style.visibility = 'visible';");
	ExecuteJavaScriptForTests("document.getElementById('B').offsetLeft;");

	sink_->ClearMessages();
	WebDocument document = view()->GetWebView()->mainFrame()->document();
	WebAXObject root_obj = document.accessibilityObject();
	WebAXObject node_a = root_obj.childAt(0);
	WebAXObject node_b = node_a.childAt(0);
	WebAXObject node_c = node_b.childAt(0);

	accessibility->HandleAXEvent(
	node_a,
	ui::AX_EVENT_CHILDREN_CHANGED);

	accessibility->SendPendingAccessibilityEvents();
	AccessibilityHostMsg_EventParams event;
	GetLastAccEvent(&event);

	ASSERT_EQ(3U, event.update.nodes.size());
	EXPECT_EQ(node_a.axID(), event.update.node_id_to_clear);
	EXPECT_EQ(node_a.axID(), event.update.nodes[0].id);
	EXPECT_EQ(node_b.axID(), event.update.nodes[1].id);
	EXPECT_EQ(node_c.axID(), event.update.nodes[2].id);
	EXPECT_EQ(3, CountAccessibilityNodesSentToBrowser());
	}

	TEST_F(RenderAccessibilityImplTest, DetachAccessibilityObject) {
	// Test RenderAccessibilityImpl and make sure it sends the
	// proper event to the browser when an object in the tree
	// is detached, but its children are not. This can happen when
	// a layout occurs and an anonymous render block is no longer needed.
	std::string html =
	"<body aria-label='Body'>"
	"<span>1</span><span style='display:block'>2</span>"
	"</body>";
	LoadHTML(html.c_str());

	std::unique_ptr<TestRenderAccessibilityImpl> accessibility(
	new TestRenderAccessibilityImpl(frame()));
	accessibility->SendPendingAccessibilityEvents();
	EXPECT_EQ(7, CountAccessibilityNodesSentToBrowser());

	// Initially, the accessibility tree looks like this:
	//
	// Document
	// +--Body
	// +--Anonymous Block
	// +--Static Text "1"
	// +--Inline Text Box "1"
	// +--Static Text "2"
	// +--Inline Text Box "2"
	WebDocument document = view()->GetWebView()->mainFrame()->document();
	WebAXObject root_obj = document.accessibilityObject();
	WebAXObject body = root_obj.childAt(0);
	WebAXObject anonymous_block = body.childAt(0);
	WebAXObject text_1 = anonymous_block.childAt(0);
	WebAXObject text_2 = body.childAt(1);

	// Change the display of the second 'span' back to inline, which causes the
	// anonymous block to be destroyed.
	ExecuteJavaScriptForTests(
	"document.querySelectorAll('span')[1].style.display = 'inline';");
	// Force layout now.
	ExecuteJavaScriptForTests("document.body.offsetLeft;");

	// Send a childrenChanged on the body.
	sink_->ClearMessages();
	accessibility->HandleAXEvent(
	body,
	ui::AX_EVENT_CHILDREN_CHANGED);

	accessibility->SendPendingAccessibilityEvents();

	// Afterwards, the accessibility tree looks like this:
	//
	// Document
	// +--Body
	// +--Static Text "1"
	// +--Inline Text Box "1"
	// +--Static Text "2"
	// +--Inline Text Box "2"
	//
	// We just assert that there are now four nodes in the
	// accessibility tree and that only three nodes needed
	// to be updated (the body, the static text 1, and
	// the static text 2).

	AccessibilityHostMsg_EventParams event;
	GetLastAccEvent(&event);
	ASSERT_EQ(5U, event.update.nodes.size());

	EXPECT_EQ(body.axID(), event.update.nodes[0].id);
	EXPECT_EQ(text_1.axID(), event.update.nodes[1].id);
	// The third event is to update text_2, but its id changes
	// so we don't have a test expectation for it.
	}

	} // namespace content