Add Slices Data object and DB Contract

Add in a Data object used to represent one row
in a new SQLite database used for building Slices.

The database has the following schema:
- Key
- Title
- Subtitle
- Screentitle
- Icon
- Fragment
- Controller

The key is the preference key.
Title, subtitle and Icon are for UI info.
Screentitle and fragment are for the intent.
Controller is used to get dynamic ui info (like summary),
and to take actions on the slice (like a toggle).

The actual indexing and a Slice will be handled in a subsquent CL,
but a prototype can be found here: ag/3324435

Test: robotests
Bug: 67996923
Change-Id: Id91deb58a3ab89ce1dab5a3f34cdb9ade6263aa8

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

@@ -0,0 +1,122 @@
+package com.android.settings.slices;
+
+import android.content.Context;
+
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.util.Log;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+/**
+ * Defines the schema for the Slices database.
+ */
+public class SlicesDatabaseHelper extends SQLiteOpenHelper {
+
+    private static final String TAG = "SlicesDatabaseHelper";
+
+    private static final String DATABASE_NAME = "slices_index.db";
+    private static final String SHARED_PREFS_TAG = "slices_shared_prefs";
+
+    private static final int DATABASE_VERSION = 1;
+
+    public interface Tables {
+        String TABLE_SLICES_INDEX = "slices_index";
+    }
+
+    public interface IndexColumns {
+        /**
+         * Primary key of the DB. Preference key from preference controllers.
+         */
+        String KEY = "key";
+
+        /**
+         * Title of the Setting.
+         */
+        String TITLE = "title";
+
+        /**
+         * Summary / Subtitle for the setting.
+         */
+        String SUBTITLE = "subtitle";
+
+        /**
+         * Title of the Setting screen on which the Setting lives.
+         */
+        String SCREENTITLE = "screentitle";
+
+        /**
+         * Resource ID for the icon of the setting. Should be 0 for no icon.
+         */
+        String ICON_RESOURCE = "icon";
+
+        /**
+         * Classname of the fragment name of the page that hosts the setting.
+         */
+        String FRAGMENT = "fragment";
+
+        /**
+         * Class name of the controller backing the setting. Must be a
+         * {@link com.android.settings.core.BasePreferenceController}.
+         */
+        String CONTROLLER = "controller";
+    }
+
+    private static final String CREATE_SLICES_TABLE =
+            "CREATE VIRTUAL TABLE " + Tables.TABLE_SLICES_INDEX + " USING fts4" +
+                    "(" +
+                    IndexColumns.KEY +
+                    ", " +
+                    IndexColumns.TITLE +
+                    ", " +
+                    IndexColumns.SUBTITLE +
+                    ", " +
+                    IndexColumns.SCREENTITLE +
+                    ", " +
+                    IndexColumns.ICON_RESOURCE +
+                    ", " +
+                    IndexColumns.FRAGMENT +
+                    ", " +
+                    IndexColumns.CONTROLLER +
+                    ");";
+
+    private final Context mContext;
+
+    public SlicesDatabaseHelper(Context context) {
+        super(context, DATABASE_NAME, null /* CursorFactor */, DATABASE_VERSION);
+        mContext = context;
+    }
+
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        createDatabases(db);
+    }
+
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        if (oldVersion < DATABASE_VERSION) {
+            Log.d(TAG, "Reconstructing DB from " + oldVersion + "to " + newVersion);
+            reconstruct(db);
+        }
+    }
+
+    @VisibleForTesting
+    void reconstruct(SQLiteDatabase db) {
+        mContext.getSharedPreferences(SHARED_PREFS_TAG, Context.MODE_PRIVATE)
+                .edit()
+                .clear()
+                .commit();
+        dropTables(db);
+        createDatabases(db);
+    }
+
+    private void createDatabases(SQLiteDatabase db) {
+        db.execSQL(CREATE_SLICES_TABLE);
+        Log.d(TAG, "Created databases");
+    }
+
+
+    private void dropTables(SQLiteDatabase db) {
+        db.execSQL("DROP TABLE IF EXISTS " + Tables.TABLE_SLICES_INDEX);
+    }
+}