[a11y] Return nullopt on GetIndexInParent if there is a modal dialog

When a modal dialog appears, GetChildCount and ChildAtIndex just
consider the modal dialog and skip other children. Since
GetIndexInParent compares itself with all siblings to get the
index, if the parent has a modal dialog, it couldn't find anything
matched.

This CL returns nullopt on GetIndexInParent if its parent has a
modal dialog.

AX-Relnotes: n/a.
Bug: 1104282
Change-Id: I3c8b45fe96aa188fd29aa63bc5fd4b1fc0bac476
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2299664
Commit-Queue: Julie Kim <jkim@igalia.com>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790734}

chrome/browser/ui/views/accessibility/browser_accessibility_uitest_auralinux.cc

@@ -8,9 +8,11 @@
 #include "base/macros.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
+#include "chrome/browser/ui/tab_modal_confirm_dialog.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "content/public/browser/render_widget_host_view.h"
+#include "content/public/browser/web_contents.h"
 #include "content/public/test/browser_test.h"
 #include "ui/accessibility/platform/ax_platform_node.h"
 
@@ -49,6 +51,59 @@ IN_PROC_BROWSER_TEST_F(AuraLinuxAccessibilityInProcessBrowserTest,
   }
 }
 
+class TestTabModalConfirmDialogDelegate : public TabModalConfirmDialogDelegate {
+ public:
+  explicit TestTabModalConfirmDialogDelegate(content::WebContents* contents)
+      : TabModalConfirmDialogDelegate(contents) {}
+  base::string16 GetTitle() override {
+    return base::ASCIIToUTF16("Dialog Title");
+  }
+  base::string16 GetDialogMessage() override { return base::string16(); }
+
+  DISALLOW_COPY_AND_ASSIGN(TestTabModalConfirmDialogDelegate);
+};
+
+// Open a tab-modal dialog and test IndexInParent with the modal dialog.
+IN_PROC_BROWSER_TEST_F(AuraLinuxAccessibilityInProcessBrowserTest,
+                       IndexInParentWithModal) {
+  BrowserView* browser_view = BrowserView::GetBrowserViewForBrowser(browser());
+  AtkObject* native_view_accessible =
+      browser_view->GetWidget()->GetRootView()->GetNativeViewAccessible();
+  EXPECT_NE(nullptr, native_view_accessible);
+
+  // The root view has a child that is a client role for Chromium.
+  int n_children = atk_object_get_n_accessible_children(native_view_accessible);
+  ASSERT_EQ(1, n_children);
+  AtkObject* client =
+      atk_object_ref_accessible_child(native_view_accessible, 0);
+  ASSERT_EQ(0, atk_object_get_index_in_parent(client));
+
+  // Opens a tab-modal dialog.
+  content::WebContents* contents = browser_view->GetActiveWebContents();
+  auto delegate = std::make_unique<TestTabModalConfirmDialogDelegate>(contents);
+  TabModalConfirmDialog* dialog =
+      TabModalConfirmDialog::Create(std::move(delegate), contents);
+
+  // The root view still has one child that is a dialog role since if it has a
+  // modal dialog it hides the rest of the children.
+  n_children = atk_object_get_n_accessible_children(native_view_accessible);
+  ASSERT_EQ(1, n_children);
+  AtkObject* dialog_node =
+      atk_object_ref_accessible_child(native_view_accessible, 0);
+  ASSERT_EQ(0, atk_object_get_index_in_parent(dialog_node));
+
+  // The client has an invalid value for the index in parent since it's hidden
+  // by the dialog.
+  ASSERT_EQ(-1, atk_object_get_index_in_parent(client));
+
+  dialog->CloseDialog();
+  // It has a valid value for the client after the dialog is closed.
+  ASSERT_EQ(0, atk_object_get_index_in_parent(client));
+
+  g_object_unref(client);
+  g_object_unref(dialog_node);
+}
+
 static AtkObject* FindParentFrame(AtkObject* object) {
   while (object) {
     if (atk_object_get_role(object) == ATK_ROLE_FRAME)

content/browser/accessibility/browser_accessibility.cc

@@ -1496,6 +1496,10 @@ gfx::NativeViewAccessible BrowserAccessibility::ChildAtIndex(int index) {
   return child->GetNativeViewAccessible();
 }
 
+bool BrowserAccessibility::HasModalDialog() const {
+  return false;
+}
+
 gfx::NativeViewAccessible BrowserAccessibility::GetFirstChild() {
   BrowserAccessibility* child = PlatformGetFirstChild();
   if (!child)

content/browser/accessibility/browser_accessibility.h

@@ -433,6 +433,7 @@ class CONTENT_EXPORT BrowserAccessibility : public ui::AXPlatformNodeDelegate {
   gfx::NativeViewAccessible GetParent() override;
   int GetChildCount() const override;
   gfx::NativeViewAccessible ChildAtIndex(int index) override;
+  bool HasModalDialog() const override;
   gfx::NativeViewAccessible GetFirstChild() override;
   gfx::NativeViewAccessible GetLastChild() override;
   gfx::NativeViewAccessible GetNextSibling() override;

ui/accessibility/platform/ax_platform_node_base.cc

@@ -182,6 +182,11 @@ base::Optional<int> AXPlatformNodeBase::GetIndexInParent() {
     if (parent->ChildAtIndex(i) == current)
       return i;
   }
+
+  // If the parent has a modal dialog, it doesn't count other children.
+  if (parent->delegate_ && parent->delegate_->HasModalDialog())
+    return base::nullopt;
+
   NOTREACHED()
       << "Unable to find the child in the list of its parent's children.";
   return base::nullopt;

ui/accessibility/platform/ax_platform_node_delegate.h

@@ -115,6 +115,9 @@ class AX_EXPORT AXPlatformNodeDelegate {
   // Get the child of a node given a 0-based index.
   virtual gfx::NativeViewAccessible ChildAtIndex(int index) = 0;
 
+  // Returns true if it has a modal dialog.
+  virtual bool HasModalDialog() const = 0;
+
   // Gets the first child of a node, or nullptr if no children exist.
   virtual gfx::NativeViewAccessible GetFirstChild() = 0;
 

ui/accessibility/platform/ax_platform_node_delegate_base.cc

@@ -94,6 +94,10 @@ gfx::NativeViewAccessible AXPlatformNodeDelegateBase::ChildAtIndex(int index) {
   return nullptr;
 }
 
+bool AXPlatformNodeDelegateBase::HasModalDialog() const {
+  return false;
+}
+
 gfx::NativeViewAccessible AXPlatformNodeDelegateBase::GetFirstChild() {
   if (GetChildCount() > 0)
     return ChildAtIndex(0);

ui/accessibility/platform/ax_platform_node_delegate_base.h

@@ -62,6 +62,9 @@ class AX_EXPORT AXPlatformNodeDelegateBase : public AXPlatformNodeDelegate {
   // Get the child of a node given a 0-based index.
   gfx::NativeViewAccessible ChildAtIndex(int index) override;
 
+  // Returns true if it has a modal dialog.
+  bool HasModalDialog() const override;
+
   gfx::NativeViewAccessible GetFirstChild() override;
   gfx::NativeViewAccessible GetLastChild() override;
   gfx::NativeViewAccessible GetNextSibling() override;

ui/views/accessibility/view_ax_platform_node_delegate.cc

@@ -345,6 +345,10 @@ gfx::NativeViewAccessible ViewAXPlatformNodeDelegate::ChildAtIndex(int index) {
   return nullptr;
 }
 
+bool ViewAXPlatformNodeDelegate::HasModalDialog() const {
+  return GetChildWidgets().is_tab_modal_showing;
+}
+
 gfx::NativeViewAccessible ViewAXPlatformNodeDelegate::GetNSWindow() {
   NOTREACHED();
   return nullptr;

ui/views/accessibility/view_ax_platform_node_delegate.h

@@ -58,6 +58,7 @@ class ViewAXPlatformNodeDelegate : public ViewAccessibility,
   const ui::AXNodeData& GetData() const override;
   int GetChildCount() const override;
   gfx::NativeViewAccessible ChildAtIndex(int index) override;
+  bool HasModalDialog() const override;
   gfx::NativeViewAccessible GetNSWindow() override;
   gfx::NativeViewAccessible GetNativeViewAccessible() override;
   gfx::NativeViewAccessible GetParent() override;