Draw underlay behind android apps using talkback

components/exo/shell_surface.h

Index: components/exo/shell_surface.h
diff --git a/components/exo/shell_surface.h b/components/exo/shell_surface.h
index 2d445c592c85dcdebe93f96eacf862b2f151b460..4d4fd20cd79dd1c1c308b5d6872ec246ddcafd5d 100644
--- a/components/exo/shell_surface.h
+++ b/components/exo/shell_surface.h
@@ -9,6 +9,7 @@
 #include <memory>
 #include <string>
 
+#include "ash/common/system/accessibility_observer.h"
 #include "ash/common/wm/window_state_observer.h"
 #include "base/macros.h"
 #include "base/strings/string16.h"
@@ -42,6 +43,7 @@ class ShellSurface : public SurfaceDelegate,
                      public SurfaceObserver,
                      public views::WidgetDelegate,
                      public views::View,
+                     public ash::AccessibilityObserver,
                      public ash::wm::WindowStateObserver,
                      public aura::WindowObserver,
                      public WMHelper::ActivationObserver {
@@ -194,6 +196,10 @@ class ShellSurface : public SurfaceDelegate,
   // Overridden from views::View:
   gfx::Size GetPreferredSize() const override;
 
+  // Overridden from ash::AccessibilityObserver:
+  void OnAccessibilityModeChanged(
+      ash::AccessibilityNotificationVisibility notify) override;
+
   // Overridden from ash::wm::WindowStateObserver:
   void OnPreWindowStateTypeChange(ash::wm::WindowState* window_state,
                                   ash::wm::WindowStateType old_type) override;
@@ -212,6 +218,7 @@ class ShellSurface : public SurfaceDelegate,
       aura::Window* lost_active) override;
 
   // Overridden from ui::EventHandler:
+  void OnEvent(ui::Event* event) override;
   void OnKeyEvent(ui::KeyEvent* event) override;
   void OnMouseEvent(ui::MouseEvent* event) override;