Don't restore any setting that we don't think should be backed up

The ad-hoc blacklist has been replaced by a check that whitelists each restored
datum against the set of keys that we actually back up.  Keys read from the
restore data which are not found in the whitelist are not applied.

Also adds in some more debugging output, marked to be disabled for ship.
diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
index c4acf33..fb5e4e6 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
@@ -50,6 +50,7 @@
  * List of settings that are backed up are stored in the Settings.java file
  */
 public class SettingsBackupAgent extends BackupHelperAgent {
+    // STOPSHIP: set DEBUG to false
     private static final boolean DEBUG = true;
 
     private static final String KEY_SYSTEM = "system";
@@ -227,6 +228,14 @@
     }
 
     private void restoreSettings(BackupDataInput data, Uri contentUri) {
+        if (DEBUG) Log.i(TAG, "restoreSettings: " + contentUri);
+        String[] whitelist = null;
+        if (contentUri.equals(Settings.Secure.CONTENT_URI)) {
+            whitelist = Settings.Secure.SETTINGS_TO_BACKUP;
+        } else if (contentUri.equals(Settings.System.CONTENT_URI)) {
+            whitelist = Settings.System.SETTINGS_TO_BACKUP;
+        }
+
         ContentValues cv = new ContentValues(2);
         byte[] settings = new byte[data.getDataSize()];
         try {
@@ -248,9 +257,8 @@
             if (!TextUtils.isEmpty(settingName) && !TextUtils.isEmpty(settingValue)) {
                 //Log.i(TAG, "Restore " + settingName + " = " + settingValue);
 
-                // TODO: versioning rather than just an ad hoc blacklist to handle
-                // older varieties of backed-up data
-                if (invalidSavedSetting(contentUri, settingName, settingValue)) {
+                // Only restore settings in our list of known-acceptable data
+                if (invalidSavedSetting(whitelist, settingName)) {
                     continue;
                 }
 
@@ -264,20 +272,23 @@
         }
     }
 
-    private boolean invalidSavedSetting(Uri contentUri, String settingName, String settingValue) {
-        // Even if these settings were stored, don't use them on restore
-        if (contentUri.equals(Settings.Secure.CONTENT_URI)) {
-            if (settingName.equals(Settings.Secure.PREFERRED_NETWORK_MODE)
-                    || settingName.equals(Settings.Secure.PREFERRED_TTY_MODE)
-                    || settingName.equals(Settings.Secure.CDMA_CELL_BROADCAST_SMS)
-                    || settingName.equals(Settings.Secure.PREFERRED_CDMA_SUBSCRIPTION)
-                    || settingName.equals(Settings.Secure.ENHANCED_VOICE_PRIVACY_ENABLED)) {
-                if (DEBUG) Log.v(TAG, "Ignoring restore datum: " + settingName);
-                return true;
+    // Returns 'true' if the given setting is one that we refuse to restore
+    private boolean invalidSavedSetting(String[] knownNames, String candidate) {
+        // no filter? allow everything
+        if (knownNames == null) {
+            return false;
+        }
+
+        // whitelisted setting?  allow it
+        for (String name : knownNames) {
+            if (name.equals(candidate)) {
+                return false;
             }
         }
 
-        return false;
+        // refuse everything else
+        if (DEBUG) Log.v(TAG, "Ignoring restore datum: " + candidate);
+        return true;
     }
 
     private String[] copyAndSort(String[] keys) {