Rewrite scoped_ptr<T>(NULL) to use the default ctor in cc/.

cc/base/scoped_ptr_hash_map.h

 // Copyright 2012 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 CC_BASE_SCOPED_PTR_HASH_MAP_H_
 #define CC_BASE_SCOPED_PTR_HASH_MAP_H_
 
 #include <algorithm>
 #include <utility>
 
@@ skipping 55 matching lines @@
     iterator it = data_.find(k);
     if (it == data_.end())
       return 0;
     erase(it);
     return 1;
   }
 
   scoped_ptr<Value> take(iterator it) {
     DCHECK(it != data_.end());
     if (it == data_.end())
-      return scoped_ptr<Value>(NULL);
+      return scoped_ptr<Value>();
 
     Key key = it->first;
     scoped_ptr<Value> ret(it->second);
     data_.erase(it);
     data_.insert(std::pair<Key, Value*>(key, static_cast<Value*>(NULL)));
     return ret.Pass();
   }
 
   scoped_ptr<Value> take(const Key& k) {
     iterator it = find(k);
     if (it == data_.end())
-      return scoped_ptr<Value>(NULL);
+      return scoped_ptr<Value>();
 
     return take(it);
   }
 
   scoped_ptr<Value> take_and_erase(iterator it) {
     DCHECK(it != data_.end());
     if (it == data_.end())
-      return scoped_ptr<Value>(NULL);
+      return scoped_ptr<Value>();
 
     scoped_ptr<Value> ret(it->second);
     data_.erase(it);
     return ret.Pass();
   }
 
   scoped_ptr<Value> take_and_erase(const Key& k) {
     iterator it = find(k);
     if (it == data_.end())
-      return scoped_ptr<Value>(NULL);
+      return scoped_ptr<Value>();
 
     return take_and_erase(it);
   }
 
   // Returns the first element in the hash_map that matches the given key.
   // If no such element exists it returns NULL.
   Value* get(const Key& k) const {
     const_iterator it = find(k);
     if (it == end())
       return 0;
@@ skipping 31 matching lines @@
 
  private:
   Container data_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedPtrHashMap);
 };
 
 }  // namespace cc
 
 #endif  // CC_BASE_SCOPED_PTR_HASH_MAP_H_