Re-apply 'Unify dart:isolate.' with fixes for autogenerated dart2js and dartium html files.

lib/compiler/implementation/patch_parser.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("patchparser");
 #import("dart:uri");
 
 #import("tree/tree.dart", prefix: "tree");
 #import("leg.dart", prefix: 'leg');  // CompilerTask, Compiler.
 #import("apiimpl.dart");
@@ skipping 19 matching lines @@
     compiler.withCurrentElement(compilationUnit, () {
       // This patches the elements of the patch library into [library].
       // Injected elements are added directly under the compilation unit.
       // Patche elements are stored on the patched functions or classes.
       scanLibraryElements(compilationUnit, imports);
     });
     // After scanning declarations, we handle the import tags in the patch.
     // TODO(lrn): These imports end up in the original library and are in
     // scope for the original methods too. This should be fixed.
     for (tree.ScriptTag tag in imports.toLink()) {
-      compiler.scanner.importLibraryFromTag(tag, compilationUnit);
+      if (tag.isSource()) {
+        library.tags = library.tags.prepend(tag);
+
+        StringNode argument = tag.argument;
+        Uri resolved = patchUri.resolve(argument.dartString.slowToString());
+        Script script = compiler.readScript(resolved, tag);
+        CompilationUnitElement unit =
+            new CompilationUnitElement(script, library);
+        compiler.withCurrentElement(unit, () => compiler.scanner.scan(unit));
+      } else {
+        compiler.scanner.importLibraryFromTag(tag, compilationUnit);
+      }
     }
   }
 
   void scanLibraryElements(
         CompilationUnitElement compilationUnit,
         LinkBuilder<tree.ScriptTag> imports) {
     measure(() {
       // TODO(lrn): Possibly recursively handle #source directives in patch.
       leg.Script script = compilationUnit.script;
       Token tokens = new StringScanner(script.text).tokenize();
@@ skipping 223 matching lines @@
     }
   }
 
   void addMember(Element element) {
     if (isMemberPatch || (isClassPatch && element is ClassElement)) {
       element.addMetadata(popNode());
     }
     super.addMember(element);
   }
 }