[inspector] introduced stepIntoAsync for chained callbacks

src/debug/debug.h

 // 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.
 
 #ifndef V8_DEBUG_DEBUG_H_
 #define V8_DEBUG_DEBUG_H_
 
 #include "src/allocation.h"
 #include "src/arguments.h"
 #include "src/assembler.h"
@@ skipping 436 matching lines @@
   Address suspended_generator_address() {
     return reinterpret_cast<Address>(&thread_local_.suspended_generator_);
   }
 
   Address restart_fp_address() {
     return reinterpret_cast<Address>(&thread_local_.restart_fp_);
   }
 
   StepAction last_step_action() { return thread_local_.last_step_action_; }
 
+  void set_non_breakable_async_events(bool value) {
+    thread_local_.non_breakable_async_events_ = value;
+  }
+
   DebugFeatureTracker* feature_tracker() { return &feature_tracker_; }
 
  private:
   explicit Debug(Isolate* isolate);
 
   void UpdateState();
   void UpdateHookOnFunctionCall();
   void Unload();
   void SetNextBreakId() {
     thread_local_.break_id_ = ++thread_local_.break_count_;
@@ skipping 148 matching lines @@
     // Value of the accumulator at the point of entering the debugger.
     Object* return_value_;
 
     // The suspended generator object to track when stepping.
     Object* suspended_generator_;
 
     // The new frame pointer to drop to when restarting a frame.
     Address restart_fp_;
 
     int async_task_count_;
+    bool non_breakable_async_events_;

[Yang, 2017/01/30 13:30:14]

Can we have a comment here?

[kozy, 2017/01/30 16:58:00]

Removed.

   };
 
   // Storage location for registers when handling debug break calls
   ThreadLocal thread_local_;
 
   Isolate* isolate_;
 
   friend class Isolate;
   friend class DebugScope;
   friend class DisableBreak;
@@ skipping 115 matching lines @@
                                   Handle<Code> code);
   static bool DebugBreakSlotIsPatched(Address pc);
   static void ClearDebugBreakSlot(Isolate* isolate, Address pc);
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_DEBUG_DEBUG_H_