[inspector] gracefully handle stack overflows in the inspector.

test/debugger/test-api.js

 // Copyright 2016 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.
 
 "use strict";
 
 // If true, prints all messages sent and received by inspector.
 const printProtocolMessages = false;
 
 // The active wrapper instance.
@@ skipping 801 matching lines @@
       case "exception":
       case "promiseRejection":
         debugEvent = this.DebugEvent.Exception;
         break;
       default:
         // TODO(jgruber): More granularity.
         debugEvent = this.DebugEvent.Break;
         break;
     }
 
+    if (!params.callFrames[0]) return;
+
     // Skip break events in this file.
     if (params.callFrames[0].location.scriptId == this.thisScriptId) return;
 
     // TODO(jgruber): Arguments as needed.
     let execState = { frames : params.callFrames,
                       prepareStep : this.execStatePrepareStep.bind(this),
                       evaluateGlobal :
                         (expr) => this.execStateEvaluateGlobal(expr),
                       frame : (index) => this.execStateFrame(
                           index ? params.callFrames[index]
@@ skipping 51 matching lines @@
     debug.instance = new DebugWrapper();
     debug.instance.enable();
   }
   return debug.instance;
 }});
 
 Object.defineProperty(debug, 'ScopeType', { get: function() {
   const instance = debug.Debug;
   return instance.ScopeType;
 }});