Fix Chrome OS virtual keyboard accessibility

chrome/browser/ui/aura/accessibility/automation_manager_aura_browsertest.cc

+// Copyright 2017 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 "chrome/browser/ui/aura/accessibility/automation_manager_aura.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_window.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/ui_test_utils.h"
+#include "content/public/browser/browser_accessibility_state.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/test/browser_test_utils.h"
+#include "ui/accessibility/ax_node_data.h"
+
+namespace {
+
+// Given an AXTreeSourceAura and a node within that tree, recursively search
+// for all nodes who have a child tree id of |target_ax_tree_id|, meaning
+// that they're a parent of a particular web contents.
+void FindAllHostsOfWebContentsWithAXTreeID(
+    AXTreeSourceAura* tree,
+    views::AXAuraObjWrapper* node,
+    int target_ax_tree_id,
+    std::vector<views::AXAuraObjWrapper*>* web_hosts) {
+  ui::AXNodeData node_data;
+  tree->SerializeNode(node, &node_data);
+  if (node_data.GetIntAttribute(ui::AX_ATTR_CHILD_TREE_ID) ==
+      target_ax_tree_id) {
+    web_hosts->push_back(node);
+  }
+
+  std::vector<views::AXAuraObjWrapper*> children;
+  tree->GetChildren(node, &children);
+  for (auto* child : children) {
+    FindAllHostsOfWebContentsWithAXTreeID(tree, child, target_ax_tree_id,
+                                          web_hosts);
+  }
+}
+
+}  // namespace
+
+typedef InProcessBrowserTest AutomationManagerAuraBrowserTest;
+
+// A WebContents can be "hooked up" to the Chrome OS Desktop accessibility
+// tree two different ways: via its aura::Window, and via a views::WebView.
+// This test makes sure that we don't hook up both simultaneously, leading
+// to the same web page appearing in the overall tree twice.
+IN_PROC_BROWSER_TEST_F(AutomationManagerAuraBrowserTest, WebAppearsOnce) {
+  content::BrowserAccessibilityState::GetInstance()->EnableAccessibility();
+
+  AutomationManagerAura* manager = AutomationManagerAura::GetInstance();
+  manager->Enable(browser()->profile());
+  auto* tree = manager->current_tree_.get();
+
+  ui_test_utils::NavigateToURL(
+      browser(),
+      GURL("data:text/html;charset=utf-8,<button autofocus>Click me</button>"));
+
+  auto* web_contents = browser()->tab_strip_model()->GetActiveWebContents();
+
+  WaitForAccessibilityTreeToContainNodeWithName(web_contents, "Click me");
+
+  auto* frame_host = web_contents->GetMainFrame();
+  int ax_tree_id = frame_host->GetAXTreeID();
+  ASSERT_GT(ax_tree_id, 0);
+
+  std::vector<views::AXAuraObjWrapper*> web_hosts;
+  FindAllHostsOfWebContentsWithAXTreeID(tree, tree->GetRoot(), ax_tree_id,
+                                        &web_hosts);
+
+  EXPECT_EQ(1U, web_hosts.size());
+  if (web_hosts.size() == 1) {
+    ui::AXNodeData node_data;
+    tree->SerializeNode(web_hosts[0], &node_data);
+    EXPECT_EQ(ui::AX_ROLE_WEB_VIEW, node_data.role);
+  } else {
+    for (size_t i = 0; i < web_hosts.size(); i++) {
+      ui::AXNodeData node_data;
+      tree->SerializeNode(web_hosts[i], &node_data);
+      LOG(ERROR) << i << ": " << node_data.ToString();
+    }
+  }
+}