Revert 269415 "Introduce a new framework for back-and-forth trac..."

trunk/src/base/prefs/pref_filter.h

Index: trunk/src/base/prefs/pref_filter.h
===================================================================
--- trunk/src/base/prefs/pref_filter.h	(revision 269437)
+++ trunk/src/base/prefs/pref_filter.h	(working copy)
@@ -7,8 +7,6 @@
 
 #include <string>
 
-#include "base/callback_forward.h"
-#include "base/memory/scoped_ptr.h"
 #include "base/prefs/base_prefs_export.h"
 
 namespace base {
@@ -20,25 +18,15 @@
 // Currently supported only by JsonPrefStore.
 class BASE_PREFS_EXPORT PrefFilter {
  public:
-  // A callback to be invoked when |prefs| have been read (and possibly
-  // pre-modified) and are now ready to be handed back to this callback's
-  // builder. |schedule_write| indicates whether a write should be immediately
-  // scheduled (typically because the |prefs| were pre-modified).
-  typedef base::Callback<void(scoped_ptr<base::DictionaryValue> prefs,
-                              bool schedule_write)> PostFilterOnLoadCallback;
-
   virtual ~PrefFilter() {}
 
-  // This method is given ownership of the |pref_store_contents| read from disk
-  // before the underlying PersistentPrefStore gets to use them. It must hand
-  // them back via |post_filter_on_load_callback|, but may modify them first.
-  // Note: This method is asynchronous, which may make calls like
-  // PersistentPrefStore::ReadPrefs() asynchronous. The owner of filtered
-  // PersistentPrefStores should handle this to make the reads look synchronous
-  // to external users (see SegregatedPrefStore::ReadPrefs() for an example).
-  virtual void FilterOnLoad(
-      const PostFilterOnLoadCallback& post_filter_on_load_callback,
-      scoped_ptr<base::DictionaryValue> pref_store_contents) = 0;
+  // Receives notification when the pref store data has been loaded but before
+  // Observers are notified.
+  // Changes made by a PrefFilter during FilterOnLoad do not result in
+  // notifications to |PrefStore::Observer|s.
+  // Implementations should return true if they modify the dictionary, to allow
+  // the changes to be persisted.
+  virtual bool FilterOnLoad(base::DictionaryValue* pref_store_contents) = 0;
 
   // Receives notification when a pref store value is changed, before Observers
   // are notified.