Polymer transformer logs now show on the frontend for pub serve.

pkg/polymer/lib/src/build/script_compactor.dart

 // Copyright (c) 2013, 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.
 
 /// Transfomer that combines multiple dart script tags into a single one.
 library polymer.src.build.script_compactor;
 
 import 'dart:async';
 import 'dart:convert';
 
@@ skipping 11 matching lines @@
 import 'package:code_transformers/resolver.dart';
 import 'package:code_transformers/src/dart_sdk.dart';
 import 'package:template_binding/src/mustache_tokens.dart' show MustacheTokens;
 
 import 'package:polymer_expressions/expression.dart' as pe;
 import 'package:polymer_expressions/parser.dart' as pe;
 import 'package:polymer_expressions/visitor.dart' as pe;
 
 import 'import_inliner.dart' show ImportInliner; // just for docs.
 import 'common.dart';
+import 'wrapped_logger.dart';
 
 /// Combines Dart script tags into a single script tag, and creates a new Dart
 /// file that calls the main function of each of the original script tags.
 ///
 /// This transformer assumes that all script tags point to external files. To
 /// support script tags with inlined code, use this transformer after running
 /// [ImportInliner] on an earlier phase.
 ///
 /// Internally, this transformer will convert each script tag into an import
 /// statement to a library, and then uses `initPolymer` (see polymer.dart)  to
@@ skipping 93 matching lines @@
   _ResolvedTypes types;
 
   /// The resolver instance associated with a single run of this transformer.
   Resolver resolver;
 
   /// Code generator used to create the static initialization for smoke.
   final generator = new SmokeCodeGenerator();
 
   _SubExpressionVisitor expressionVisitor;
 
-  _ScriptCompactor(Transform transform, this.options, this.resolvers)
+  _ScriptCompactor(Transform transform, options, this.resolvers)
       : transform = transform,
-        logger = transform.logger,
+        options = options,
+        logger = options.releaseMode ? transform.logger :
+          new WrappedLogger(transform, convertErrorsToWarnings: true),
         docId = transform.primaryInput.id,
         bootstrapId = transform.primaryInput.id.addExtension('_bootstrap.dart');
 
   Future apply() =>
       _loadDocument()
       .then(_loadEntryLibraries)
       .then(_processHtml)
-      .then(_emitNewEntrypoint);
+      .then(_emitNewEntrypoint)
+      .then((_) {
+        // Write out the logs collected by our [WrappedLogger].
+        if (options.injectBuildLogsInOutput && logger is WrappedLogger) {
+          return logger.writeOutput();
+        }
+      });
 
   /// Loads the primary input as an html document.
   Future _loadDocument() =>
       readPrimaryAsHtml(transform).then((doc) { document = doc; });
 
   /// Populates [entryLibraries] as a list containing the asset ids of each
   /// library loaded on a script tag. The actual work of computing this is done
   /// in an earlier phase and emited in the `entrypoint._data` asset.
   Future _loadEntryLibraries(_) =>
       transform.readInputAsString(docId.addExtension('._data')).then((data) {
@@ skipping 254 matching lines @@
   /// Writes the final output for the bootstrap Dart file and entrypoint HTML
   /// file.
   void _emitFiles(_) {
     StringBuffer code = new StringBuffer()..writeln(MAIN_HEADER);
     Map<AssetId, String> prefixes = {};
     int i = 0;
     for (var id in entryLibraries) {
       var url = assetUrlFor(id, bootstrapId, logger);
       if (url == null) continue;
       code.writeln("import '$url' as i$i;");
+      if (options.injectBuildLogsInOutput) {
+        code.writeln("import 'package:polymer/src/build/log_injector.dart';");
+      }
       prefixes[id] = 'i$i';
       i++;
     }
 
     // Include smoke initialization.
     generator.writeImports(code);
     generator.writeTopLevelDeclarations(code);
     code.writeln('\nvoid main() {');
     code.write('  useGeneratedCode(');
     generator.writeStaticConfiguration(code);
     code.writeln(');');
+
+    if (options.injectBuildLogsInOutput) {
+      code.writeln('  new LogInjector().injectLogsFromUrl();');
+    }
+
     if (experimentalBootstrap) {
       code.write('  startPolymer([');
     } else {
       code.write('  configureForDeployment([');
     }
 
     // Include initializers to switch from mirrors_loader to static_loader.
     if (!initializers.isEmpty) {
       code.writeln();
       for (var init in initializers) {
         var initCode = init.asCode(prefixes[init.assetId]);
         code.write("      $initCode,\n");
       }
       code.writeln('    ]);');
     } else {
       if (experimentalBootstrap) logger.warning(NO_INITIALIZERS_ERROR);
       code.writeln(']);');
     }
     if (!experimentalBootstrap) {
       code.writeln('  i${entryLibraries.length - 1}.main();');
     }
+
+    // End of main().
     code.writeln('}');
     transform.addOutput(new Asset.fromString(bootstrapId, code.toString()));
 
 
     // Emit the bootstrap .dart file
     var srcUrl = path.url.basename(bootstrapId.path);
     document.body.nodes.add(parseFragment(
-          '<script type="application/dart" src="$srcUrl"></script>'));
+        '<script type="application/dart" src="$srcUrl"></script>'));
+
+    // Add the styles for the logger widget.
+    if (options.injectBuildLogsInOutput) {
+      document.head.append(parseFragment(
+          '<link rel="stylesheet" type="text/css"'
+              'href="packages/polymer/src/build/log_injector.css">'));
+    }
+
     transform.addOutput(new Asset.fromString(docId, document.outerHtml));
   }
 
   _spanForNode(analyzer.Element context, AstNode node) {
     var file = resolver.getSourceFile(context);
     return file.span(node.offset, node.end);
   }
 }
 
 abstract class _Initializer {
@@ skipping 343 matching lines @@
   for (var c in combinators) {
     if (c is ShowElementCombinator) {
       var show = c.shownNames.toSet();
       elements.retainWhere((e) => show.contains(e.displayName));
     } else if (c is HideElementCombinator) {
       var hide = c.hiddenNames.toSet();
       elements.removeWhere((e) => hide.contains(e.displayName));
     }
   }
 }