Use ATK_ROLE_APPLICATION for toplevel applications

The accessibility code for Aura on Linux was using the ATK_ROLE_EMBEDDED
role for elements with the role ax::mojom::Role::kApplication so that
it would not apply to ARIA applications. To be consistent with other
applications, ATK_ROLE_APPLICATION is more appropriate. We only use this
when the element is the root of the accessibility tree.

TEST=accessibility_unittests --gtest_filter=AXPlatformNodeAuraLinuxTest.*

Bug: 867006
Change-Id: I6c64b142cf3307c906f73235ed8247e828cd2394
Reviewed-on: https://chromium-review.googlesource.com/1148397Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577920}

ui/accessibility/platform/ax_platform_node_auralinux.cc

@@ -980,9 +980,13 @@ AtkRole AXPlatformNodeAuraLinux::GetAtkRole() {
     case ax::mojom::Role::kAnnotation:
       return ATK_ROLE_PANEL;
     case ax::mojom::Role::kApplication:
-      // Don't use ATK_ROLE_APPLICATION, which is for top level app windows,
-      // not ARIA applications.
-      return ATK_ROLE_EMBEDDED;
+      // Only use ATK_ROLE_APPLICATION for elements with no parent, since it
+      // is only for top level app windows and not ARIA applications.
+      if (!GetParent()) {
+        return ATK_ROLE_APPLICATION;
+      } else {
+        return ATK_ROLE_EMBEDDED;
+      }
     case ax::mojom::Role::kArticle:
       return ATK_ROLE_ARTICLE;
     case ax::mojom::Role::kAudio:

ui/accessibility/platform/ax_platform_node_auralinux_unittest.cc

@@ -143,6 +143,7 @@ TEST_F(AXPlatformNodeAuraLinuxTest, TestAtkObjectRole) {
   AXNodeData root;
   root.id = 1;
   root.child_ids.push_back(2);
+  root.role = ax::mojom::Role::kApplication;
 
   AXNodeData child;
   child.id = 2;
@@ -150,6 +151,12 @@ TEST_F(AXPlatformNodeAuraLinuxTest, TestAtkObjectRole) {
   Init(root, child);
   AXNode* child_node = GetRootNode()->children()[0];
 
+  AtkObject* root_obj(AtkObjectFromNode(GetRootNode()));
+  ASSERT_TRUE(ATK_IS_OBJECT(root_obj));
+  g_object_ref(root_obj);
+  EXPECT_EQ(ATK_ROLE_APPLICATION, atk_object_get_role(root_obj));
+  g_object_unref(root_obj);
+
   child.role = ax::mojom::Role::kAlert;
   child_node->SetData(child);
   AtkObject* child_obj(AtkObjectFromNode(child_node));
@@ -173,6 +180,14 @@ TEST_F(AXPlatformNodeAuraLinuxTest, TestAtkObjectRole) {
   g_object_ref(child_obj);
   EXPECT_EQ(ATK_ROLE_CANVAS, atk_object_get_role(child_obj));
   g_object_unref(child_obj);
+
+  child.role = ax::mojom::Role::kApplication;
+  child_node->SetData(child);
+  child_obj = AtkObjectFromNode(child_node);
+  ASSERT_TRUE(ATK_IS_OBJECT(child_obj));
+  g_object_ref(child_obj);
+  EXPECT_EQ(ATK_ROLE_EMBEDDED, atk_object_get_role(child_obj));
+  g_object_unref(child_obj);
 }
 
 TEST_F(AXPlatformNodeAuraLinuxTest, TestAtkObjectState) {