Adding the ability to customize the subtitle on an unavailable slice

When a slice is depending on some setting and the setting is off,
it shows "depends on another setting".
Add an new attribute for Preference to customize the subtitle when
a slice is unavailable.

Bug: 118399193
Test: Robo test on com.android.settings.slices, com.android.settings.core
Change-Id: I84a8400295b36abb357e5baf98e9be3a8d6ea897

src/com/android/settings/slices/SliceData.java

@@ -28,7 +28,6 @@ import java.lang.annotation.RetentionPolicy;
  * Note that {@link #mKey} is treated as a primary key for this class and determines equality.
  */
 public class SliceData {
-
     /**
      * Flags indicating the UI type of the Slice.
      */
@@ -76,6 +75,8 @@ public class SliceData {
 
     private final boolean mIsDynamicSummaryAllowed;
 
+    private final String mUnavailableSliceSubtitle;
+
     public String getKey() {
         return mKey;
     }
@@ -124,6 +125,10 @@ public class SliceData {
         return mIsDynamicSummaryAllowed;
     }
 
+    public String getUnavailableSliceSubtitle() {
+        return mUnavailableSliceSubtitle;
+    }
+
     private SliceData(Builder builder) {
         mKey = builder.mKey;
         mTitle = builder.mTitle;
@@ -137,6 +142,7 @@ public class SliceData {
         mSliceType = builder.mSliceType;
         mIsPlatformDefined = builder.mIsPlatformDefined;
         mIsDynamicSummaryAllowed = builder.mIsDynamicSummaryAllowed;
+        mUnavailableSliceSubtitle = builder.mUnavailableSliceSubtitle;
     }
 
     @Override
@@ -178,6 +184,8 @@ public class SliceData {
 
         private boolean mIsDynamicSummaryAllowed;
 
+        private String mUnavailableSliceSubtitle;
+
         public Builder setKey(String key) {
             mKey = key;
             return this;
@@ -238,6 +246,12 @@ public class SliceData {
             return this;
         }
 
+        public Builder setUnavailableSliceSubtitle(
+                String unavailableSliceSubtitle) {
+            mUnavailableSliceSubtitle = unavailableSliceSubtitle;
+            return this;
+        }
+
         public SliceData build() {
             if (TextUtils.isEmpty(mKey)) {
                 throw new InvalidSliceDataException("Key cannot be empty");