Trim a line on the right before determining max breakpoint column

runtime/observatory/lib/src/debugger/debugger_location.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.
 
 part of debugger;
 
 class DebuggerLocation {
   DebuggerLocation.file(this.script, this.line, this.col);
   DebuggerLocation.func(this.function);
   DebuggerLocation.error(this.errorMessage);
@@ skipping 402 matching lines @@
 
       } else {
         // Complete the column.
         int lineNum = int.parse(lineStr);
         var scriptLine = script.getLine(lineNum);
         if (!scriptLine.possibleBpt) {
           return [];
         }
         var sharedPrefix = '${script.name}:${lineStr}:';
         List completions = [];
-        int maxCol = scriptLine.text.runes.length;
+        int maxCol = scriptLine.text.trimRight().runes.length;
         for (int i = 1; i <= maxCol; i++) {
           var currentColStr = i.toString();
           if (currentColStr.startsWith(colStr)) {
             completions.add('${sharedPrefix}${currentColStr} ');
           }
         }
         return completions;
       }
     }
   }
@@ skipping 11 matching lines @@
     return 'invalid source location (${errorMessage})';
   }
 
   Script script;
   int line;
   int col;
   ServiceFunction function;
   String errorMessage;
   bool get valid => (errorMessage == null);
 }