Add asserts and state tracking to ensure that we do not call

include/v8.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3413 matching lines @@
  * Multiple threads in V8 are allowed, but only one thread at a time
  * is allowed to use any given V8 isolate. See Isolate class
  * comments. The definition of 'using V8 isolate' includes
  * accessing handles or holding onto object pointers obtained
  * from V8 handles while in the particular V8 isolate.  It is up
  * to the user of V8 to ensure (perhaps with locking) that this
  * constraint is not violated.
  *
  * v8::Locker is a scoped lock object. While it's
  * active (i.e. between its construction and destruction) the current thread is
- * allowed to use the locked isolate. V8 guarantees that an isolate can be locked
- * by at most one thread at any time. In other words, the scope of a v8::Locker is
- * a critical section.
+ * allowed to use the locked isolate. V8 guarantees that an isolate can be
+ * locked by at most one thread at any time. In other words, the scope of a
+ * v8::Locker is a critical section.
  *
  * Sample usage:
 * \code
  * ...
  * {
  *   v8::Locker locker(isolate);
  *   v8::Isolate::Scope isolate_scope(isolate);
  *   ...
  *   // Code using V8 and isolate goes here.
  *   ...
@@ skipping 81 matching lines @@
    * for the V8 lock.
    */
   static void StartPreemption(int every_n_ms);
 
   /**
    * Stop preemption.
    */
   static void StopPreemption();
 
   /**
-   * Returns whether or not the locker for a given isolate, or default isolate if NULL is given,
-   * is locked by the current thread.
+   * Returns whether or not the locker for a given isolate, or default isolate
+   * if NULL is given, is locked by the current thread.
    */
   static bool IsLocked(Isolate* isolate = NULL);
 
   /**
    * Returns whether v8::Locker is being used by this V8 instance.
    */
   static bool IsActive() { return active_; }
 
  private:
   bool has_lock_;
@@ skipping 565 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_