Introduce per-isolate assert scopes and API to guard JS execution.

src/isolate.h

 // Copyright 2012 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 363 matching lines @@
   /* AstNode state. */                                                         \
   V(int, ast_node_id, 0)                                                       \
   V(unsigned, ast_node_count, 0)                                               \
   V(bool, microtask_pending, false)                                            \
   V(bool, autorun_microtasks, true)                                            \
   V(HStatistics*, hstatistics, NULL)                                           \
   V(HTracer*, htracer, NULL)                                                   \
   V(CodeTracer*, code_tracer, NULL)                                            \
   V(bool, fp_stubs_generated, false)                                           \
   V(int, max_available_threads, 0)                                             \
+  V(uint32_t, per_isolate_assert_data, 0xFFFFFFFFu)                            \
   ISOLATE_INIT_SIMULATOR_LIST(V)                                               \
   ISOLATE_DEBUGGER_INIT_LIST(V)
 
 #define THREAD_LOCAL_TOP_ACCESSOR(type, name)                        \
   inline void set_##name(type v) { thread_local_top_.name##_ = v; }  \
   inline type name() const { return thread_local_top_.name##_; }
 
 
 class Isolate {
   // These forward declarations are required to make the friend declarations in
@@ skipping 1155 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_