Revert "GTTF: Add missing virtual destructors."

base/prefs/public/pref_member.h

Index: base/prefs/public/pref_member.h
diff --git a/base/prefs/public/pref_member.h b/base/prefs/public/pref_member.h
index a395ab1b41b1e3c3d7891b546aad5b4380488046..52a91b5f3ed214dc50c9aa51b6f65c51bee3c089 100644
--- a/base/prefs/public/pref_member.h
+++ b/base/prefs/public/pref_member.h
@@ -42,8 +42,7 @@ class PrefServiceBase;
 
 namespace subtle {
 
-class BASE_PREFS_EXPORT PrefMemberBase
-    : public NON_EXPORTED_BASE(PrefObserver) {
+class BASE_PREFS_EXPORT PrefMemberBase : public PrefObserver {
  public:
   // Type of callback you can register if you need to know the name of
   // the pref that is changing.