[debugger] expose side-effect free evaluate to 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 659 matching lines @@
       }
     }
 
     return { value : () => value,
              isUndefined : () => isUndefined,
              type : () => obj.type,
              className : () => obj.className
            };
   }
 
-  evaluateOnCallFrame(frame, expr) {
+  evaluateOnCallFrame(frame, expr, throw_on_side_effect = false) {
     const frameid = frame.callFrameId;
     const {msgid, msg} = this.createMessage(
         "Debugger.evaluateOnCallFrame",
         { callFrameId : frameid,
-          expression : expr
+          expression : expr,
+          throwOnSideEffect : throw_on_side_effect,
         });
     this.sendMessage(msg);
     const reply = this.takeReplyChecked(msgid);
 
     const result = reply.result.result;
     return this.reconstructRemoteObject(result);
   }
 
   frameReceiver(frame) {
     return this.reconstructRemoteObject(frame.this);
@@ skipping 24 matching lines @@
       for (let i = 0; i < frame.scopeChain.length; i++) {
         scopes.push(this.execStateScope(frame, i));
       }
       return scopes;
     }
 
     return { sourceColumn : () => column,
              sourceLine : () => line + 1,
              sourceLineText : () => loc.sourceText,
              sourcePosition : () => loc.position,
-             evaluate : (expr) => this.evaluateOnCallFrame(frame, expr),
+             evaluate : (expr, throw_on_side_effect) =>
+                 this.evaluateOnCallFrame(frame, expr, throw_on_side_effect),
              functionName : () => frame.functionName,
              func : () => func,
              index : () => index,
              localCount : () => this.execStateFrameLocalCount(frame),
              localName : (ix) => this.execStateFrameLocalName(frame, ix),
              localValue: (ix) => this.execStateFrameLocalValue(frame, ix),
              receiver : () => this.frameReceiver(frame),
              restart : () => this.execStateFrameRestart(frame),
              returnValue : () => this.frameReturnValue(frame),
              scopeCount : () => frame.scopeChain.length,
@@ skipping 147 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;
 }});