Accessible name for nameless window selector textfield

This is split out from the CL to test all widgets and views for nameless
focusable objects. See crrev.com/c/951933.

Bug: 819350
Change-Id: I4eb266d06d6468657b2cf00873a601efb976166c
Reviewed-on: https://chromium-review.googlesource.com/952327Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542245}

ash/ash_strings.grd

@@ -535,6 +535,11 @@ This file contains the strings for ash.
         No recent items
       </message>
 
+      <!-- Window Selector -->
+      <message name="IDS_ASH_WINDOW_SELECTOR_INPUT_FILTER_ACCESSIBLE_NAME" desc="The accessible name for the window selector filter search input box.">
+        Type the name of an app or document
+      </message>
+
       <!-- Status tray charging strings. -->
       <message name="IDS_ASH_STATUS_TRAY_LOW_POWER_CHARGER_TITLE" desc="The title of a notification indicating that a low-current USB charger has been connected.">
         Low-power charger connected

ash/wm/overview/window_selector.cc

@@ -18,6 +18,7 @@
 #include "ash/screen_util.h"
 #include "ash/shelf/shelf.h"
 #include "ash/shell.h"
+#include "ash/strings/grit/ash_strings.h"
 #include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/overview/overview_utils.h"
 #include "ash/wm/overview/overview_window_drag_controller.h"
@@ -37,6 +38,8 @@
 #include "base/metrics/user_metrics.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/vector_icons/vector_icons.h"
+#include "ui/accessibility/ax_enums.mojom.h"
+#include "ui/base/l10n/l10n_util.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/display/screen.h"
@@ -45,6 +48,7 @@
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/paint_vector_icon.h"
 #include "ui/gfx/skia_util.h"
+#include "ui/views/accessibility/view_accessibility.h"
 #include "ui/views/border.h"
 #include "ui/views/controls/image_view.h"
 #include "ui/views/controls/textfield/textfield.h"
@@ -194,6 +198,8 @@ views::Widget* CreateTextFilter(views::TextfieldController* controller,
   textfield->SetTextColor(IsNewOverviewUi() ? kTextFilterTextColor
                                             : kOldTextFilterTextColor);
   textfield->SetFontList(font_list);
+  textfield->SetAccessibleName(l10n_util::GetStringUTF16(
+      IDS_ASH_WINDOW_SELECTOR_INPUT_FILTER_ACCESSIBLE_NAME));
 
   views::ImageView* image_view = new views::ImageView();
   image_view->SetImage(image);