Add accessible names to the launcher buttons

ash/launcher/tabbed_launcher_button.cc

Index: ash/launcher/tabbed_launcher_button.cc
diff --git a/ash/launcher/tabbed_launcher_button.cc b/ash/launcher/tabbed_launcher_button.cc
index 09da1a92c9c792d86f0ce47f22254da6a32b0e58..84d061ed678598c6d10d1b00d5dac35d5a980e83 100644
--- a/ash/launcher/tabbed_launcher_button.cc
+++ b/ash/launcher/tabbed_launcher_button.cc
@@ -8,6 +8,7 @@
 
 #include "ash/launcher/launcher_button_host.h"
 #include "grit/ui_resources.h"
+#include "ui/base/accessibility/accessible_view_state.h"
 #include "ui/base/animation/multi_animation.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
@@ -162,6 +163,11 @@ void TabbedLauncherButton::OnMouseExited(const views::MouseEvent& event) {
   hover_controller_.Hide();
 }
 
+void TabbedLauncherButton::GetAccessibleState(ui::AccessibleViewState* state) {
+  state->role = ui::AccessibilityTypes::ROLE_PUSHBUTTON;
+  state->name = host_->GetAccessibleName(this);
+}
+
 // static
 TabbedLauncherButton::ImageSet* TabbedLauncherButton::CreateImageSet(
     int normal_id,