Put conditional operators on the left.

lib/src/source_visitor.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 dart_style.src.source_visitor;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';
 
@@ skipping 353 matching lines @@
     }
 
     visitNodes(directives, between: oneOrTwoNewlines);
     visitNodes(node.declarations,
         before: twoNewlines, between: oneOrTwoNewlines);
   }
 
   visitConditionalExpression(ConditionalExpression node) {
     _writer.nestExpression();
     visit(node.condition);
-    space();
 
     _writer.startSpan();
-    token(node.question);
 
     // If we split after one clause in a conditional, always split after both.
     _writer.startMultisplit();
     _writer.multisplit(nest: true, space: true);
+    token(node.question);
+    space();
+
     visit(node.thenExpression);
 
+    _writer.multisplit(nest: true, space: true);
+    token(node.colon);
     space();
-    token(node.colon);
-    _writer.multisplit(nest: true, space: true);
+
     visit(node.elseExpression);
 
     _writer.endMultisplit();
     _writer.endSpan();
     _writer.unnest();
   }
 
   visitConstructorDeclaration(ConstructorDeclaration node) {
     visitMemberMetadata(node.metadata);
 
@@ skipping 1406 matching lines @@
   /// Gets the 1-based line number that the beginning of [token] lies on.
   int _startLine(Token token) => _lineInfo.getLocation(token.offset).lineNumber;
 
   /// Gets the 1-based line number that the end of [token] lies on.
   int _endLine(Token token) => _lineInfo.getLocation(token.end).lineNumber;
 
   /// Gets the 1-based column number that the beginning of [token] lies on.
   int _startColumn(Token token) =>
       _lineInfo.getLocation(token.offset).columnNumber;
 }