Get rid of doctype warning in analyzer

pkg/polymer/lib/src/compiler.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.
 
 library compiler;
 
 import 'dart:async';
 import 'dart:collection' show SplayTreeMap;
 
 import 'package:csslib/visitor.dart' show StyleSheet, treeToDebugString;
@@ skipping 12 matching lines @@
 import 'compiler_options.dart';
 import 'utils.dart';
 
 /**
  * Parses an HTML file [contents] and returns a DOM-like tree.
  * Note that [contents] will be a [String] if coming from a browser-based
  * [FileSystem], or it will be a [List<int>] if running on the command line.
  *
  * Adds emitted error/warning to [messages], if [messages] is supplied.
  */
-Document parseHtml(contents, String sourcePath, Messages messages) {
+Document parseHtml(contents, String sourcePath, Messages messages,
+    bool checkDocType) {
   var parser = new HtmlParser(contents, generateSpans: true,
       sourceUrl: sourcePath);
   var document = parser.parse();
 
   // Note: errors aren't fatal in HTML (unless strict mode is on).
   // So just print them as warnings.
   for (var e in parser.errors) {
-    messages.warning(e.message, e.span);
+    if (checkDocType || e.errorCode != 'expected-doctype-but-got-start-tag') {
+      messages.warning(e.message, e.span);
+    }
   }
   return document;
 }
 
 /** Compiles an application written with Dart web components. */
 class Compiler {
   final FileSystem fileSystem;
   final CompilerOptions options;
   final List<SourceFile> files = <SourceFile>[];
 
@@ skipping 58 matching lines @@
 
   /**
    * Asynchronously parse [inputFile] and transitively discover web components
    * to load and parse. Returns a future that completes when all files are
    * processed.
    */
   Future _parseAndDiscover(String inputFile) {
     _tasks = new FutureGroup();
     _processed = new Set();
     _processed.add(inputFile);
-    _tasks.add(_parseHtmlFile(new UrlInfo(inputFile, inputFile, null)));
+    _tasks.add(_parseHtmlFile(new UrlInfo(inputFile, inputFile, null), true));
     return _tasks.future;
   }
 
   void _processHtmlFile(UrlInfo inputUrl, SourceFile file) {
     if (file == null) return;
 
     bool isEntryPoint = _processed.length == 1;
 
     files.add(file);
 
@@ skipping 44 matching lines @@
   void _loadFile(UrlInfo urlInfo, Future loadAndParse(UrlInfo inputUrl)) {
     if (urlInfo == null) return;
     var resolvedPath = urlInfo.resolvedPath;
     if (!_processed.contains(resolvedPath)) {
       _processed.add(resolvedPath);
       _tasks.add(loadAndParse(urlInfo));
     }
   }
 
   /** Parse an HTML file. */
-  Future _parseHtmlFile(UrlInfo inputUrl) {
+  Future _parseHtmlFile(UrlInfo inputUrl, [bool checkDocType = false]) {
     var filePath = inputUrl.resolvedPath;
     return fileSystem.readTextOrBytes(filePath)
         .catchError((e) => _readError(e, inputUrl))
         .then((source) {
           if (source == null) return;
           var file = new SourceFile(filePath);
           file.document = _time('Parsed', filePath,
-              () => parseHtml(source, filePath, _messages));
+              () => parseHtml(source, filePath, _messages, checkDocType));
           _processHtmlFile(inputUrl, file);
         });
   }
 
   /** Parse a stylesheet file. */
   Future _parseCssFile(UrlInfo inputUrl) {
     if (!options.emulateScopedCss) {
       return new Future<SourceFile>.value(null);
     }
     var filePath = inputUrl.resolvedPath;
@@ skipping 144 matching lines @@
     message.write(logMessage);
     var filename = path.basename(filePath);
     for (int i = (60 - logMessage.length - filename.length); i > 0 ; i--) {
       message.write(' ');
     }
     message.write(filename);
     return time(message.toString(), callback,
         printTime: options.verbose || printTime);
   }
 }