Add more per-tab preferences.

chrome/browser/prefs/pref_service.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/prefs/pref_service.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 727 matching lines @@
          "invalid preference type: " << orig_type;
 
   // Hand off ownership.
   default_store_->SetDefaultValue(path, scoped_value.release());
 
   // Register with sync if necessary.
   if (sync_status == SYNCABLE_PREF && pref_sync_associator_.get())
     pref_sync_associator_->RegisterPref(path);
 }
 
+void PrefService::UnregisterPreference(const char* path) {
+  DCHECK(CalledOnValidThread());
+
+  Preference p(this, path, Value::TYPE_NULL);
+  PreferenceSet::const_iterator it = prefs_.find(&p);
+  if (it == prefs_.end()) {
+    NOTREACHED() << "Trying to unregister an unregistered pref: " << path;
+    return;
+  }
+
+  prefs_.erase(it);
+  default_store_->RemoveDefaultValue(path);
+  if (pref_sync_associator_.get() &&
+      pref_sync_associator_->IsPrefRegistered(path)) {
+    pref_sync_associator_->UnregisterPref(path);
+  }
+}
+
 void PrefService::ClearPref(const char* path) {
   DCHECK(CalledOnValidThread());
 
   const Preference* pref = FindPreference(path);
   if (!pref) {
     NOTREACHED() << "Trying to clear an unregistered pref: " << path;
     return;
   }
   user_pref_store_->RemoveValue(path);
 }
@@ skipping 163 matching lines @@
   return pref_value_store()->PrefValueFromDefaultStore(name_.c_str());
 }
 
 bool PrefService::Preference::IsUserModifiable() const {
   return pref_value_store()->PrefValueUserModifiable(name_.c_str());
 }
 
 bool PrefService::Preference::IsExtensionModifiable() const {
   return pref_value_store()->PrefValueExtensionModifiable(name_.c_str());
 }