Correctly recognize emptiness of IDMap.

base/id_map.h

 // Copyright (c) 2006-2008 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.
 
 #ifndef BASE_ID_MAP_H_
 #define BASE_ID_MAP_H_
 
 #include <set>
 
 #include "base/basictypes.h"
@@ skipping 64 matching lines @@
 
     if (iteration_depth_ == 0) {
       Releaser<OS, 0>::release(i->second);
       data_.erase(i);
     } else {
       removed_ids_.insert(id);
     }
   }
 
   bool IsEmpty() const {
-    return data_.empty();
+    return size() == 0u;
   }
 
   T* Lookup(KeyType id) const {
     typename HashTable::const_iterator i = data_.find(id);
     if (i == data_.end())
       return NULL;
     return i->second;
   }
 
   size_t size() const {
-    return data_.size();
+    return data_.size() - removed_ids_.size();
   }
 
   // It is safe to remove elements from the map during iteration. All iterators
   // will remain valid.
   template<class ReturnType>
   class Iterator {
    public:
     Iterator(IDMap<T>* map)
         : map_(map),
           iter_(map_->data_.begin()) {
@@ skipping 82 matching lines @@
 
   HashTable data_;
 
   // See description above setter.
   bool check_on_null_data_;
 
   DISALLOW_COPY_AND_ASSIGN(IDMap);
 };
 
 #endif  // BASE_ID_MAP_H_