Add support for enabling DCHECKs in release mode

src/string-stream.cc

 // Copyright 2014 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/string-stream.h"
 
 #include "src/handles-inl.h"
 #include "src/prototype.h"
 
 namespace v8 {
@@ skipping 264 matching lines @@
 
 void StringStream::ClearMentionedObjectCache(Isolate* isolate) {
   isolate->set_string_stream_current_security_token(NULL);
   if (isolate->string_stream_debug_object_cache() == NULL) {
     isolate->set_string_stream_debug_object_cache(new DebugObjectCache(0));
   }
   isolate->string_stream_debug_object_cache()->Clear();
 }
 
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
 bool StringStream::IsMentionedObjectCacheClear(Isolate* isolate) {
   return isolate->string_stream_debug_object_cache()->length() == 0;
 }
 #endif
 
 
 bool StringStream::Put(String* str) {
   return Put(str, 0, str->length());
 }
 
@@ skipping 260 matching lines @@
   }
   MemCopy(new_space, space_, *bytes);
   *bytes = new_bytes;
   DeleteArray(space_);
   space_ = new_space;
   return new_space;
 }
 
 
 } }  // namespace v8::internal