Replace base::NullableString16(bool) usage with default constructor.

base/strings/nullable_string16.h

 // Copyright (c) 2010 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_STRINGS_NULLABLE_STRING16_H_
 #define BASE_STRINGS_NULLABLE_STRING16_H_
 
 #include <iosfwd>
 
 #include "base/base_export.h"
 #include "base/strings/string16.h"
 
 namespace base {
 
 // This class is a simple wrapper for string16 which also contains a null
 // state.  This should be used only where the difference between null and
 // empty is meaningful.
 class NullableString16 {
  public:
   NullableString16() : is_null_(true) { }
-  explicit NullableString16(bool is_null) : is_null_(is_null) { }

[michaeln, 2013/06/17 23:48:12]

i guess we never construct the oddball non-null empty value?

   NullableString16(const string16& string, bool is_null)
       : string_(string), is_null_(is_null) {
   }
 
   const string16& string() const { return string_; }
   bool is_null() const { return is_null_; }
 
  private:
   string16 string_;
   bool is_null_;
@@ skipping 10 matching lines @@
 BASE_EXPORT std::ostream& operator<<(std::ostream& out,
                                      const NullableString16& value);
 
 }  // namespace
 
 // TODO(avi) update users of NullableString16 to use the namespace and remove
 // this "using".
 using base::NullableString16;
 
 #endif  // BASE_STRINGS_NULLABLE_STRING16_H_