Announce for accessiblity when taskbar is invoked/closed

Test: Manual
Bug: 265620540
Change-Id: I6660be7716ec59c765f3d54f8fe9889eaaf56e10

quickstep/src/com/android/launcher3/taskbar/TaskbarStashController.java

@@ -600,6 +600,7 @@ public class TaskbarStashController implements TaskbarControllers.LoggableTaskba
                 if (!mIsStashed) {
                     tryStartTaskbarTimeout();
                 }
+                mControllers.taskbarViewController.announceForAccessibility();
             }
         });
     }

quickstep/src/com/android/launcher3/taskbar/TaskbarView.java

@@ -16,15 +16,18 @@
 package com.android.launcher3.taskbar;
 
 import static android.content.pm.PackageManager.FEATURE_PC;
+import static android.view.accessibility.AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED;
 
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.graphics.Rect;
+import android.os.Bundle;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.accessibility.AccessibilityNodeInfo;
 import android.widget.FrameLayout;
 
 import androidx.annotation.LayoutRes;
@@ -153,7 +156,26 @@ public class TaskbarView extends FrameLayout implements FolderIcon.FolderIconPar
 
         // TODO: Disable touch events on QSB otherwise it can crash.
         mQsb = LayoutInflater.from(context).inflate(R.layout.search_container_hotseat, this, false);
+    }
 
+    @Override
+    public boolean performAccessibilityActionInternal(int action, Bundle arguments) {
+        if (action == AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS) {
+            announceForAccessibility(mContext.getString(R.string.taskbar_a11y_shown_title));
+        } else if (action == AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS) {
+            announceForAccessibility(mContext.getString(R.string.taskbar_a11y_hidden_title));
+        }
+        return super.performAccessibilityActionInternal(action, arguments);
+
+    }
+
+    protected void announceAccessibilityChanges() {
+        this.performAccessibilityAction(
+                isVisibleToUser() ? AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS
+                        : AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS, null);
+
+        ActivityContext.lookupContext(getContext()).getDragLayer()
+                .sendAccessibilityEvent(TYPE_WINDOW_CONTENT_CHANGED);
     }
 
     private int getColorWithGivenLuminance(int color, float luminance) {

quickstep/src/com/android/launcher3/taskbar/TaskbarViewController.java

@@ -189,6 +189,13 @@ public class TaskbarViewController implements TaskbarControllers.LoggableTaskbar
         mActivity.addOnDeviceProfileChangeListener(mDeviceProfileChangeListener);
     }
 
+    /**
+     * Announcement for Accessibility when Taskbar stashes/unstashes.
+     */
+    public void announceForAccessibility() {
+        mTaskbarView.announceAccessibilityChanges();
+    }
+
     public void onDestroy() {
         LauncherAppState.getInstance(mActivity).getModel().removeCallbacks(mModelCallbacks);
         mActivity.removeOnDeviceProfileChangeListener(mDeviceProfileChangeListener);