Add support for enabling DCHECKs in release mode

src/assert-scope.h

 // Copyright 2013 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.
 
 #ifndef V8_ASSERT_SCOPE_H_
 #define V8_ASSERT_SCOPE_H_
 
 #include <stdint.h>
 #include "src/base/macros.h"
 
@@ skipping 52 matching lines @@
   class DataBit;
 
   Isolate* isolate_;
   uint32_t old_data_;
 
   DISALLOW_COPY_AND_ASSIGN(PerIsolateAssertScope);
 };
 
 
 template <PerThreadAssertType type, bool allow>
-#ifdef DEBUG
-class PerThreadAssertScopeDebugOnly : public
-    PerThreadAssertScope<type, allow> {
+#if DCHECK_IS_ON
+class PerThreadAssertScopeDebugOnly : public PerThreadAssertScope<type, allow> {
 #else
 class PerThreadAssertScopeDebugOnly {
  public:
   PerThreadAssertScopeDebugOnly() { }
 #endif
 };
 
 
 template <PerIsolateAssertType type, bool allow>
-#ifdef DEBUG
-class PerIsolateAssertScopeDebugOnly : public
-    PerIsolateAssertScope<type, allow> {
+#if DCHECK_IS_ON
+class PerIsolateAssertScopeDebugOnly
+    : public PerIsolateAssertScope<type, allow> {
  public:
   explicit PerIsolateAssertScopeDebugOnly(Isolate* isolate)
       : PerIsolateAssertScope<type, allow>(isolate) { }
 #else
 class PerIsolateAssertScopeDebugOnly {
  public:
   explicit PerIsolateAssertScopeDebugOnly(Isolate* isolate) { }
 #endif
 };
 
@@ skipping 77 matching lines @@
 // Scope to document where we do not expect deoptimization.
 typedef PerIsolateAssertScopeDebugOnly<COMPILATION_ASSERT, false>
     DisallowCompilation;
 
 // Scope to introduce an exception to DisallowDeoptimization.
 typedef PerIsolateAssertScopeDebugOnly<COMPILATION_ASSERT, true>
     AllowCompilation;
 } }  // namespace v8::internal
 
 #endif  // V8_ASSERT_SCOPE_H_