Do not redact string extras which exclusively contain helpful system information.

Also, include the length of redacted strings.

Test: produce a bugreport and validate the expected strings are present
Change-Id: Ib1e5e18290f4a4854b0594c7e939f9392b8ac4bb

services/core/java/com/android/server/notification/NotificationRecord.java

@@ -585,7 +585,8 @@ public final class NotificationRecord {
                     pw.println("null");
                 } else {
                     pw.print(val.getClass().getSimpleName());
-                    if (redact && (val instanceof CharSequence || val instanceof String)) {
+                    if (redact && (val instanceof CharSequence) && shouldRedactStringExtra(key)) {
+                        pw.print(String.format(" [length=%d]", ((CharSequence) val).length()));
                         // redact contents from bugreports
                     } else if (val instanceof Bitmap) {
                         pw.print(String.format(" (%dx%d)",
@@ -611,6 +612,19 @@ public final class NotificationRecord {
         }
     }
 
+    private boolean shouldRedactStringExtra(String key) {
+        if (key == null) return true;
+        switch (key) {
+            // none of these keys contain user-related information; they do not need to be redacted
+            case Notification.EXTRA_SUBSTITUTE_APP_NAME:
+            case Notification.EXTRA_TEMPLATE:
+            case "android.support.v4.app.extra.COMPAT_TEMPLATE":
+                return false;
+            default:
+                return true;
+        }
+    }
+
     @Override
     public final String toString() {
         return String.format(