Change close button style of user chooser following the spec.

Bug: 845805
Change-Id: Ia9783b8499ed61e29a7257ba25f414a7db216dc8
Reviewed-on: https://chromium-review.googlesource.com/1100727Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Commit-Queue: Tatsuhisa Yamaguchi <yamaguchi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567599}

ash/ash_strings.grd

@@ -1448,6 +1448,9 @@ This file contains the strings for ash.
       <message name="IDS_ASH_DIALOG_DONT_SHOW_AGAIN" desc="Label for checkbox dismissing show of a dialog.">
         Don't show again
       </message>
+      <message name="IDS_ASH_WINDOW_CONTROL_ACCNAME_CLOSE" desc="The accessible name for a close button on a window frame.">
+        Close
+      </message>
 
       <!-- Power off menu  -->
       <message name="IDS_ASH_POWER_BUTTON_MENU_POWER_OFF_BUTTON" desc="Text shown on power off button in power button menu.">

ash/system/unified/user_chooser_view.cc

@@ -12,6 +12,7 @@
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_popup_utils.h"
 #include "ash/system/tray/tri_view.h"
+#include "ash/system/unified/top_shortcut_button.h"
 #include "ash/system/unified/top_shortcuts_view.h"
 #include "ash/system/unified/unified_system_tray_controller.h"
 #include "ash/system/user/rounded_image_view.h"
@@ -59,7 +60,7 @@ base::string16 GetUserItemAccessibleString(int user_index) {
 
 namespace {
 
-class CloseButton : public views::ImageButton, public views::ButtonListener {
+class CloseButton : public TopShortcutButton, public views::ButtonListener {
  public:
   explicit CloseButton(UnifiedSystemTrayController* controller);
 
@@ -73,12 +74,10 @@ class CloseButton : public views::ImageButton, public views::ButtonListener {
 };
 
 CloseButton::CloseButton(UnifiedSystemTrayController* controller)
-    : ImageButton(this), controller_(controller) {
-  // TODO(crbug.com/845805): Replace the close button icon.
-  gfx::ImageSkia icon =
-      gfx::CreateVectorIcon(kOverviewWindowCloseIcon, kMenuIconColor);
-  SetImage(views::Button::STATE_NORMAL, icon);
-}
+    : TopShortcutButton(this,
+                        kOverviewWindowCloseIcon,
+                        IDS_ASH_WINDOW_CONTROL_ACCNAME_CLOSE),
+      controller_(controller) {}
 
 void CloseButton::ButtonPressed(views::Button* sender, const ui::Event& event) {
   controller_->TransitionToMainView(true /* restore_focus */);