Add content description in the tutorial dialog

Add content description in the message of tutorial dialog in
accessibility button mode. It prevents Talkback speaking out "%s",
which is not the content we want.

Bug: 135497450
Test: test with TalkBack
Change-Id: If7ce8a957cbb44a12124bc3436d8e32ef0f0da83
diff --git a/res/values/strings.xml b/res/values/strings.xml
index b215ef5..ea0f8bc 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -4856,7 +4856,7 @@
     <!-- Title for the Accessibility tutorial dialog in gesture navigation settings. [CHAR LIMIT=50] -->
     <string name="accessibility_tutorial_dialog_title_gesture_settings">Use new accessibility gesture</string>
     <!-- Message for the Accessibility tutorial dialog when user enables an accessibility service while using the 3-button nav bar. [CHAR LIMIT=NONE] -->
-    <string name="accessibility_tutorial_dialog_message_button">To turn this service on or off, tap the accessibility button<xliff:g id="accessibility_icon" example="[Icon]">%s</xliff:g>on the bottom of your screen.\n\nTo switch between services, touch &amp; hold the accessibility button.</string>
+    <string name="accessibility_tutorial_dialog_message_button">To turn this service on or off, tap the accessibility button <xliff:g id="accessibility_icon" example="[Icon]">%s</xliff:g> on the bottom of your screen.\n\nTo switch between services, touch &amp; hold the accessibility button.</string>
     <!-- Message for the Accessibility tutorial dialog when user enables an accessibility service while using gesture navigation and touch exploration is not enabled. [CHAR LIMIT=NONE] -->
     <string name="accessibility_tutorial_dialog_message_gesture_without_talkback">To turn this service on or off, swipe up from the bottom of the screen with two fingers.\n\nTo switch between services, swipe up with two fingers and hold.</string>
     <!-- Message for the Accessibility tutorial dialog when user enables an accessibility service while using gesture navigation and touch exploration is enabled. [CHAR LIMIT=NONE] -->
diff --git a/src/com/android/settings/accessibility/AccessibilityGestureNavigationTutorial.java b/src/com/android/settings/accessibility/AccessibilityGestureNavigationTutorial.java
index e7b2b82..153fa19 100644
--- a/src/com/android/settings/accessibility/AccessibilityGestureNavigationTutorial.java
+++ b/src/com/android/settings/accessibility/AccessibilityGestureNavigationTutorial.java
@@ -179,10 +179,12 @@
         final int indexIconStart = messageString.indexOf("%s");
         final int indexIconEnd = indexIconStart + 2;
         final Drawable icon = context.getDrawable(R.drawable.ic_accessibility_new);
+        final ImageSpan imageSpan = new ImageSpan(icon);
+        imageSpan.setContentDescription("");
         icon.setTint(getThemeAttrColor(context, android.R.attr.textColorPrimary));
         icon.setBounds(0, 0, lineHeight, lineHeight);
         spannableMessage.setSpan(
-                new ImageSpan(icon), indexIconStart, indexIconEnd,
+                imageSpan, indexIconStart, indexIconEnd,
                 Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
 
         return spannableMessage;