Convert Window role to ATK_ROLE_FRAME for Aura Linux

Instead of using ATK_ROLE_WINDOW by default for the internal Window
accessibility role, use ATK_ROLE_FRAME. ATK_ROLE_FRAME is used for
windows that have titlebars and buttons, while ATK_ROLE_WINDOW is
reserved for those that don't. Since most windows have buttons and a
titlebar in Chromium, ATK_ROLE_FRAME is probably a better default.

TEST=accessibility_unittests --gtest_filter=AXPlatformNodeAuraLinuxTest.*

Bug: 867006
Change-Id: Ia0366f7088465f123f00e250c4cc6f7393c0c64e
Reviewed-on: https://chromium-review.googlesource.com/1148445
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578665}

ui/accessibility/platform/ax_platform_node_auralinux.cc

@@ -352,7 +352,7 @@ static gfx::Point FindAtkObjectParentCoords(AtkObject* atk_object) {
   if (!atk_object)
     return gfx::Point(0, 0);
 
-  if (atk_object_get_role(atk_object) == ATK_ROLE_WINDOW) {
+  if (atk_object_get_role(atk_object) == ATK_ROLE_FRAME) {
     int x, y;
     atk_component_get_extents(ATK_COMPONENT(atk_object),
         &x, &y, nullptr, nullptr, ATK_XY_WINDOW);
@@ -1294,7 +1294,10 @@ AtkRole AXPlatformNodeAuraLinux::GetAtkRole() {
     case ax::mojom::Role::kWebView:
       return ATK_ROLE_DOCUMENT_WEB;
     case ax::mojom::Role::kWindow:
-      return ATK_ROLE_WINDOW;
+      // In ATK elements with ATK_ROLE_FRAME are windows with titles and
+      // buttons, while those with ATK_ROLE_WINDOW are windows without those
+      // elements.
+      return ATK_ROLE_FRAME;
     case ax::mojom::Role::kClient:
     case ax::mojom::Role::kDesktop:
     case ax::mojom::Role::kFigcaption:

ui/accessibility/platform/ax_platform_node_auralinux_unittest.cc

@@ -188,6 +188,14 @@ TEST_F(AXPlatformNodeAuraLinuxTest, TestAtkObjectRole) {
   g_object_ref(child_obj);
   EXPECT_EQ(ATK_ROLE_EMBEDDED, atk_object_get_role(child_obj));
   g_object_unref(child_obj);
+
+  child.role = ax::mojom::Role::kWindow;
+  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_FRAME, atk_object_get_role(child_obj));
+  g_object_unref(child_obj);
 }
 
 TEST_F(AXPlatformNodeAuraLinuxTest, TestAtkObjectState) {