Make isolate.h usable without objects-inl.h header.

src/debug/debug.cc

 // Copyright 2012 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/debug/debug.h"
 
 #include "src/api.h"
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/compilation-cache.h"
 #include "src/compiler.h"
 #include "src/deoptimizer.h"
 #include "src/execution.h"
 #include "src/frames-inl.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/global-handles.h"
+#include "src/isolate-inl.h"
 #include "src/list.h"
 #include "src/log.h"
 #include "src/messages.h"
 #include "src/snapshot/natives.h"
 
 #include "include/v8-debug.h"
 
 namespace v8 {
 namespace internal {
 
@@ skipping 2589 matching lines @@
 }
 
 
 void LockingCommandMessageQueue::Clear() {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 }  // namespace internal
 }  // namespace v8