Add support for enabling DCHECKs in release mode

src/optimizing-compiler-thread.cc

Index: src/optimizing-compiler-thread.cc
diff --git a/src/optimizing-compiler-thread.cc b/src/optimizing-compiler-thread.cc
index acff5b6b634372c6f25e71b533da9e4933a6e448..10ac919a9d78cc9442e4d09d6ee166a3cd03bc68 100644
--- a/src/optimizing-compiler-thread.cc
+++ b/src/optimizing-compiler-thread.cc
@@ -73,7 +73,7 @@ OptimizingCompilerThread::~OptimizingCompilerThread() {
 
 
 void OptimizingCompilerThread::Run() {
-#ifdef DEBUG
+#if DCHECK_IS_ON
   { base::LockGuard<base::Mutex> lock_guard(&thread_id_mutex_);
     thread_id_ = ThreadId::Current().ToInteger();
   }
@@ -425,7 +425,7 @@ void OptimizingCompilerThread::AddToOsrBuffer(OptimizedCompileJob* job) {
 }
 
 
-#ifdef DEBUG
+#if DCHECK_IS_ON
 bool OptimizingCompilerThread::IsOptimizerThread(Isolate* isolate) {
   return isolate->concurrent_recompilation_enabled() &&
          isolate->optimizing_compiler_thread()->IsOptimizerThread();