Add support for enabling DCHECKs in release mode

src/scanner-character-streams.cc

 // Copyright 2011 the V8 project 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 "src/v8.h"
 
 #include "src/scanner-character-streams.h"
 
 #include "include/v8.h"
 #include "src/handles.h"
@@ skipping 216 matching lines @@
                          raw_data_length_);
   raw_character_position_ = char_position + i;
   return i;
 }
 
 
 static const byte kUtf8MultiByteMask = 0xC0;
 static const byte kUtf8MultiByteCharFollower = 0x80;
 
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
 static const byte kUtf8MultiByteCharStart = 0xC0;
 static bool IsUtf8MultiCharacterStart(byte first_byte) {
   return (first_byte & kUtf8MultiByteMask) == kUtf8MultiByteCharStart;
 }
 #endif
 
 
 static bool IsUtf8MultiCharacterFollower(byte later_byte) {
   return (later_byte & kUtf8MultiByteMask) == kUtf8MultiByteCharFollower;
 }
@@ skipping 211 matching lines @@
         int end_position)
     : Utf16CharacterStream(),
       source_(data),
       raw_data_(data->GetTwoByteData(start_position)) {
   buffer_cursor_ = raw_data_,
   buffer_end_ = raw_data_ + (end_position - start_position);
   pos_ = start_position;
 }
 
 } }  // namespace v8::internal