Frog changes (in experimental) to get frog integrated into the test infrastructure.

options.dart

 // Copyright (c) 2011, 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.
 
 /** General options used by the compiler. */
 Options options;
 
 /** Extracts options from command-line arguments. */
-void parseOptions(String homedir, List<String> args) {
+void parseOptions(String homedir, List<String> args, FileSystem files) {
   assert(options == null);
-  options = new Options(homedir, args);
+  options = new Options(homedir, args, files);
 }
 
 // TODO(sigmund): make into a generic option parser...
 class Options {
   /** Location of corelib and other special dart libraries. */
   String libDir;
 
   /* The top-level dart script to compile. */
   String dartScript;
 
@@ skipping 15 matching lines @@
   bool throwOnFatal = false;
   bool showInfo = false;
   bool showWarnings = true;
 
   /**
    * Options to be used later for passing to the generated code. These are all
    * the arguments after the first dart script, if any.
    */
   List<String> childArgs;
 
-  Options(String homedir, List<String> args) {
+  Options(String homedir, List<String> args, FileSystem files) {
     libDir = homedir + '/lib'; // Default value for --libdir.
     bool ignoreUnrecognizedFlags = false;
+    bool passedLibDir = false;
+    childArgs = [];
 
     // Start from 2 to skip arguments representing the compiler command
     // (node/python followed by frogsh/frog.py).
     // TODO(jimhug): break on switch cases seems broken?
     loop: for (int i = 2; i < args.length; i++) {
       var arg = args[i];
 
       switch (arg) {
         case '--enable_leg':
           enableLeg = true;
@@ skipping 39 matching lines @@
 
         case '--compile-only':
           // As opposed to compiling and running, the default behavior.
           compileOnly = true;
           continue loop;
 
         default:
           if (arg.endsWith('.dart')) {
             dartScript = arg;
             childArgs = args.getRange(i + 1, args.length - i - 1);
-            return;
+            break loop;
           } else if (arg.startsWith('--out=')) {
             outfile = arg.substring('--out='.length);
           } else if (arg.startsWith('--libdir=')) {
             libDir = arg.substring('--libdir='.length);
+            passedLibDir = true;
           } else {
             if (!ignoreUnrecognizedFlags) {
               print('unrecognized flag: "$arg"');
             }
           }
       }
     }
-    childArgs = [];
+
+    if (!passedLibDir && !files.fileExists(libDir)) {
+      // Try locally
+      var temp = 'frog/lib';
+      if (files.fileExists(temp)) {
+        libDir = temp;
+      } else {
+        libDir = 'lib';
+      }
+    }
   }
 }