Revert "Support sourceing files in patches."

lib/compiler/implementation/patch_parser.dart

Index: lib/compiler/implementation/patch_parser.dart
diff --git a/lib/compiler/implementation/patch_parser.dart b/lib/compiler/implementation/patch_parser.dart
index 4ea29b45cbeef6b9e44b3472f1f9bf186d2ef70c..c975ca0a343a36c722142099b64402dc4c0ed473 100644
--- a/lib/compiler/implementation/patch_parser.dart
+++ b/lib/compiler/implementation/patch_parser.dart
@@ -37,12 +37,7 @@ class PatchParserTask extends leg.CompilerTask {
     // 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()) {
-      if (tag.isSource()) {
-        Uri resolved = patchUri.resolve(tag.argument.dartString.slowToString());
-        compiler.scanner.sourceTagInLibrary(tag, resolved, library);
-      } else {
-        compiler.scanner.importLibraryFromTag(tag, compilationUnit);
-      }
+      compiler.scanner.importLibraryFromTag(tag, compilationUnit);
     }
   }