Draft change to use base::Closure instead of PrefObserver in PrefChangeRegistrar.

chrome/browser/api/prefs/pref_member.cc

Index: chrome/browser/api/prefs/pref_member.cc
diff --git a/chrome/browser/api/prefs/pref_member.cc b/chrome/browser/api/prefs/pref_member.cc
index e81b13a61081620b7495dbb94ac4f697fe0d344d..ee0ca9869cddf69db657e6d292dae5745b125fc2 100644
--- a/chrome/browser/api/prefs/pref_member.cc
+++ b/chrome/browser/api/prefs/pref_member.cc
@@ -37,12 +37,17 @@ void PrefMemberBase::Init(const char* pref_name,
       << pref_name << " not registered.";
 
   // Add ourselves as a pref observer so we can keep our local value in sync.
-  prefs_->AddPrefObserver(pref_name, this);
+  prefs_->AddPrefObserver(pref_name,
+                          base::Bind(&PrefMemberBase::OnPreferenceChanged,
+                                     base::Unretained(this), prefs, pref_name));
 }
 
 void PrefMemberBase::Destroy() {
   if (prefs_ && !pref_name_.empty()) {
-    prefs_->RemovePrefObserver(pref_name_.c_str(), this);
+    prefs_->RemovePrefObserver(pref_name_.c_str(),
+                               base::Bind(&PrefMemberBase::OnPreferenceChanged,
+                                          base::Unretained(this),
+                                          prefs_, pref_name_.c_str()));
     prefs_ = NULL;
   }
 }