Implement list isolates command

tools/ddbg.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Simple interactive debugger shell that connects to the Dart VM's debugger
 // connection port.
 
 import "dart:io";
 import "dart:json" as json;
 import "dart:utf";
@@ skipping 30 matching lines @@
   pl <id> <idx> [<len>] Print list element/slice
   pc <id> Print class info for given id
   ll  List loaded libraries
   plib <id> Print library info for given library id
   slib <id> <true|false> Set library id debuggable
   pg <id> Print all global variables visible within given library id
   ls <lib_id> List loaded scripts in library
   gs <lib_id> <script_url> Get source text of script in library
   tok <lib_id> <script_url> Get line and token table of script in library
   epi <none|all|unhandled>  Set exception pause info
+  li List ids of all isolates in the VM
   i <id> Interrupt execution of given isolate id
   h   Print help
 """);
 }
 
 
 void quitShell() {
   vmSubscription.cancel();
   vmSock.close();
   stdinSubscription.cancel();
@@ skipping 125 matching lines @@
                 "params": { "isolateId" : isolate_id,
                             "libraryId": int.parse(args[1]),
                             "url": args[2] } };
     sendCmd(cmd).then((result) => handleGetLineTableResponse(result));
   } else if (command == "epi" && args.length == 2) {
     var cmd = { "id": seqNum,
                 "command":  "setPauseOnException",
                 "params": { "isolateId" : isolate_id,
                             "exceptions": args[1] } };
     sendCmd(cmd).then((result) => handleGenericResponse(result));
+  } else if (command == "li") {
+    var cmd = { "id": seqNum, "command": "getIsolateIds" };
+    sendCmd(cmd).then((result) => handleGetIsolatesResponse(result));
   } else if (command == "i" && args.length == 2) {
     var cmd = { "id": seqNum,
                 "command": "interrupt",
                 "params": { "isolateId": int.parse(args[1]) } };
     sendCmd(cmd).then((result) => handleGenericResponse(result));
   } else if (command == "q") {
     quitShell();
   } else if (command == "h") {
     printHelp();
   } else {
@@ skipping 124 matching lines @@
 }
 
 
 handleGetLineTableResponse(response) {
   Map result = response["result"];
   var info = result["lines"];
   print("Line info table:\n$info");
 }
 
 
+handleGetIsolatesResponse(response) {
+  Map result = response["result"];
+  print("Isolates: ${result["isolateIds"]}");
+}
+
+
 void handleGetLibraryResponse(response) {
   Map result = response["result"];
   List libs = result["libraries"];
   print("Loaded libraries:");
   print(libs);
   for (int i = 0; i < libs.length; i++) {
     print("  ${libs[i]["id"]} ${libs[i]["url"]}");
   }
 }
 
@@ skipping 243 matching lines @@
       process.stdin.close();
       process.exitCode.then((int exitCode) {
         print('${arguments.join(" ")} exited with $exitCode');
       });
       debuggerMain();
     });
   } else {
     debuggerMain();
   }
 }