Print the first compile-time error in console.

dart/site/try/src/interaction_manager.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 trydart.interaction_manager;
 
 import 'dart:html';
 
 import 'dart:convert' show
     JSON;
@@ skipping 148 matching lines @@
 
   /// Called when notified about a project file changed (on the server).
   void onProjectFileFsEvent(MessageEvent e);
 
   /// Called every [HEARTBEAT_INTERVAL].
   void onHeartbeat(Timer timer);
 
   /// Called by [:window.onMessage.listen:].
   void onWindowMessage(MessageEvent event);
 
-  void onCompilationFailed();
+  void onCompilationFailed(String firstError);
 
   void onCompilationDone();
 
   /// Called when a compilation is starting, but just before sending the
   /// initiating message to the compiler isolate.
   void compilationStarting();
 
   // TODO(ahe): Remove this from InteractionManager, but not from InitialState.
   void consolePrintLine(line);
 
@@ skipping 98 matching lines @@
   }
 
   void onProjectFileFsEvent(MessageEvent e) {
     return state.onProjectFileFsEvent(e);
   }
 
   void onHeartbeat(Timer timer) => state.onHeartbeat(timer);
 
   void onWindowMessage(MessageEvent event) => state.onWindowMessage(event);
 
-  void onCompilationFailed() => state.onCompilationFailed();
+  void onCompilationFailed(String firstError) {
+    return state.onCompilationFailed(firstError);
+  }
 
   void onCompilationDone() => state.onCompilationDone();
 
   void compilationStarting() => state.compilationStarting();
 
   void consolePrintLine(line) => state.consolePrintLine(line);
 
   void aboutToRun() => state.aboutToRun();
 
   void onIframeError(ErrorMessage message) => state.onIframeError(message);
@@ skipping 409 matching lines @@
     if (window.parent != window) {
       // Test support.
       // TODO(ahe): Use '/' instead of '*' when Firefox is upgraded to version
       // 30 across build bots.  Support for '/' was added in version 29, and we
       // support the two most recent versions.
       window.parent.postMessage('$line\n', '*');
     }
     outputDiv.appendText('$line\n');
   }
 
-  void onCompilationFailed() {
-    consolePrintLine('Compilation failed.');
+  void onCompilationFailed(String firstError) {
+    if (firstError == null) {
+      consolePrintLine('Compilation failed.');
+    } else {
+      consolePrintLine('Compilation failed: $firstError');
+    }
   }
 
   void onCompilationDone() {
     context.isFirstCompile = false;
     context.elapsedCompilationTime.stop();
     Duration compilationDuration = context.elapsedCompilationTime.elapsed;
     context.elapsedCompilationTime.reset();
     print('Compilation took $compilationDuration.');
     if (context.compilerConsole.parent != null) {
       context.compilerConsole.remove();
@@ skipping 601 matching lines @@
     token = token.next;
     kind = token.kind;
   }
   return token;
 }
 
 String extractQuote(String string) {
   StringQuoting q = StringValidator.quotingFromString(string);
   return (q.raw ? 'r' : '') + (q.quoteChar * q.leftQuoteLength);
 }