Make source information on conditions mandatory in CPS

pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart

 // Copyright (c) 2014, 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.
 
 library tree_ir_nodes;
 
 import '../constants/values.dart' as values;
 import '../dart_types.dart' show DartType, InterfaceType, TypeVariableType;
 import '../elements/elements.dart';
 import '../io/source_information.dart' show SourceInformation;
@@ skipping 331 matching lines @@
 
 /**
  * Apply a built-in operator.
  *
  * It must be known that the arguments have the proper types.
  * Null is not a valid argument to any of the built-in operators.
  */
 class ApplyBuiltinOperator extends Expression {
   BuiltinOperator operator;
   List<Expression> arguments;
+  SourceInformation sourceInformation;
 
-  ApplyBuiltinOperator(this.operator, this.arguments);
+  ApplyBuiltinOperator(this.operator, this.arguments, this.sourceInformation);
 
   accept(ExpressionVisitor visitor) {
     return visitor.visitApplyBuiltinOperator(this);
   }
   accept1(ExpressionVisitor1 visitor, arg) {
     return visitor.visitApplyBuiltinOperator(this, arg);
   }
 }
 
 class ApplyBuiltinMethod extends Expression {
@@ skipping 231 matching lines @@
   accept1(StatementVisitor1 visitor, arg) => visitor.visitThrow(this, arg);
 }
 
 /**
  * A conditional branch based on the true value of an [Expression].
  */
 class If extends Statement {
   Expression condition;
   Statement thenStatement;
   Statement elseStatement;
+  SourceInformation sourceInformation;
 
   Statement get next => null;
   void set next(Statement s) => throw 'UNREACHABLE';
 
-  If(this.condition, this.thenStatement, this.elseStatement);
+  If(this.condition,
+     this.thenStatement,
+     this.elseStatement,
+     this.sourceInformation);
 
   accept(StatementVisitor visitor) => visitor.visitIf(this);
   accept1(StatementVisitor1 visitor, arg) => visitor.visitIf(this, arg);
 }
 
 class ExpressionStatement extends Statement {
   Statement next;
   Expression expression;
 
   ExpressionStatement(this.expression, this.next);
@@ skipping 994 matching lines @@
 
   /// Number of uses of the current fallthrough target.
   int get useCount => _stack.last.useCount;
 
   /// Indicate that a statement will fall through to the current fallthrough
   /// target.
   void use() {
     ++_stack.last.useCount;
   }
 }