Support tab completion of line:col in the debugger.

runtime/observatory/tests/service/add_breakpoint_rpc_test.dart

 // Copyright (c) 2015, 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.
 // VMOptions=--error_on_bad_type --error_on_bad_override
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 import 'deferred_library.dart' deferred as deferredLib;
 import 'dart:async';
-import 'dart:developer' as developer;
 
 int value = 0;
 
 int incValue(int amount) {
   value += amount;
   return amount;
 }
 
 Future testMain() async {
-  incValue(incValue(1));  // line 21
+  incValue(incValue(1));  // line 20
 
-  incValue(incValue(1));  // line 23
+  incValue(incValue(1));  // line 22
 
   await deferredLib.loadLibrary();
   deferredLib.deferredTest();
 }
 
 var tests = [
   hasPausedAtStart,
 
   // Test future breakpoints.
   (Isolate isolate) async {
     var rootLib = isolate.rootLibrary;
     await rootLib.load();
     var script = rootLib.scripts[0];
 
     // Future breakpoint.
-    var futureBpt1 = await isolate.addBreakpoint(script, 21);
+    var futureBpt1 = await isolate.addBreakpoint(script, 20);
     expect(futureBpt1.number, equals(1));
     expect(futureBpt1.resolved, isFalse);
-    expect(await futureBpt1.location.getLine(), equals(21));
+    expect(await futureBpt1.location.getLine(), equals(20));
     expect(await futureBpt1.location.getColumn(), equals(null));
 
     // Future breakpoint with specific column.
-    var futureBpt2 = await isolate.addBreakpoint(script, 21, 3);
+    var futureBpt2 = await isolate.addBreakpoint(script, 20, 3);
     expect(futureBpt2.number, equals(2));
     expect(futureBpt2.resolved, isFalse);
-    expect(await futureBpt2.location.getLine(), equals(21));
+    expect(await futureBpt2.location.getLine(), equals(20));
     expect(await futureBpt2.location.getColumn(), equals(3));
 
     var stream = await isolate.vm.getEventStream(VM.kDebugStream);
     Completer completer = new Completer();
     var subscription;
     var resolvedCount = 0;
     subscription = stream.listen((ServiceEvent event) async {
       if (event.kind == ServiceEvent.kBreakpointResolved) {
         resolvedCount++;
       }
       if (event.kind == ServiceEvent.kPauseBreakpoint) {
         subscription.cancel();
         completer.complete(null);
       }
     });
     await isolate.resume();
     await completer.future;
 
     // After resolution the breakpoints have assigned line & column.
     expect(resolvedCount, equals(2));
     expect(futureBpt1.resolved, isTrue);
-    expect(await futureBpt1.location.getLine(), equals(21));
+    expect(await futureBpt1.location.getLine(), equals(20));
     expect(await futureBpt1.location.getColumn(), equals(12));
     expect(futureBpt2.resolved, isTrue);
-    expect(await futureBpt2.location.getLine(), equals(21));
+    expect(await futureBpt2.location.getLine(), equals(20));
     expect(await futureBpt2.location.getColumn(), equals(3));
 
     // The first breakpoint hits before value is modified.
     expect((await rootLib.evaluate('value')).valueAsString, equals('0'));
 
     stream = await isolate.vm.getEventStream(VM.kDebugStream);
     completer = new Completer();
     subscription = stream.listen((ServiceEvent event) async {
       if (event.kind == ServiceEvent.kPauseBreakpoint) {
         subscription.cancel();
@@ skipping 85 matching lines @@
     expect((await isolate.removeBreakpoint(latentBpt2)).type,
            equals('Success'));
   },
 
 
   // Test resolution of column breakpoints.
   (Isolate isolate) async {
     var script = isolate.rootLibrary.scripts[0];
     // Try all columns, including some columns that are too big.
     for (int col = 1; col <= 50; col++) {
-      var bpt = await isolate.addBreakpoint(script, 21, col);
+      var bpt = await isolate.addBreakpoint(script, 20, col);
       expect(bpt.resolved, isTrue);
       int resolvedLine = await bpt.location.getLine();
       int resolvedCol = await bpt.location.getColumn();
-      print('21:${col} -> ${resolvedLine}:${resolvedCol}');
+      print('20:${col} -> ${resolvedLine}:${resolvedCol}');
       if (col <= 10) {
-        expect(resolvedLine, equals(21));
+        expect(resolvedLine, equals(20));
         expect(resolvedCol, equals(3));
       } else if (col <= 19) {
-        expect(resolvedLine, equals(21));
+        expect(resolvedLine, equals(20));
         expect(resolvedCol, equals(12));
       } else {
-        expect(resolvedLine, equals(23));
+        expect(resolvedLine, equals(22));
         expect(resolvedCol, equals(12));
       }
       expect((await isolate.removeBreakpoint(bpt)).type, equals('Success'));
     }
 
     // Make sure that a zero column is an error.
     var caughtException = false;
     try {
-      await isolate.addBreakpoint(script, 21, 0);
+      await isolate.addBreakpoint(script, 20, 0);
       expect(false, isTrue, reason:'Unreachable');
     } on ServerRpcException catch(e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kInvalidParams));
       expect(e.message,
              "addBreakpoint: invalid 'column' parameter: 0");
     }
     expect(caughtException, isTrue);
   },
 ];
 
 main(args) => runIsolateTests(args, tests,
                               testeeConcurrent: testMain,
                               pause_on_start: true);