Support user generated custom native JS classes.

pkg/compiler/lib/src/js_backend/namer.dart

Index: pkg/compiler/lib/src/js_backend/namer.dart
diff --git a/pkg/compiler/lib/src/js_backend/namer.dart b/pkg/compiler/lib/src/js_backend/namer.dart
index 14a399cd8aa583160559ad3e438647b9e1f8f7ee..43ba0e16bc7003373a0c68d8180091e3dad59a2a 100644
--- a/pkg/compiler/lib/src/js_backend/namer.dart
+++ b/pkg/compiler/lib/src/js_backend/namer.dart
@@ -634,6 +634,26 @@ class Namer {
     return invocationName(new Selector.fromElement(method));
   }
 
+  String _jsNameHelper(Element e) {
+    if (e.jsInteropName != null && e.jsInteropName.isNotEmpty)
+      return e.jsInteropName;
+    return e.isLibrary ? 'self' : e.name;
+  }
+
+  String fixedBackendPath(Element element) {

[Siggi Cherem (dart-lang), 2015/10/06 22:38:02]

+ dartdoc?

[Jacob, 2015/10/13 01:19:23]

Done.

+    if (!element.isJsInterop) return null;
+    if (element.isInstanceMember) return 'this';
+    if (element.isConstructor) return fixedBackendPath(element.enclosingClass);
+    if (element.isLibrary) return 'self';
+    var sb = new StringBuffer();
+    sb..write(_jsNameHelper(element.library));
+
+    if (element.enclosingClass != null && element.enclosingClass != element) {
+      sb..write('.')..write(_jsNameHelper(element.enclosingClass));
+    }
+    return sb.toString();
+  }
+
   /// Returns the annotated name for a variant of `call`.
   /// The result has the form:
   ///
@@ -765,6 +785,7 @@ class Namer {
     if (element.hasFixedBackendName) {
       // Certain native fields must be given a specific name. Native names must
       // not contain '$'. We rely on this to avoid clashes.
+      // TODO(jacobr): we need to relax this constraint.

[Siggi Cherem (dart-lang), 2015/10/06 22:38:02]

please file a bug to refer to it here.

[Jacob, 2015/10/13 01:19:23]

synced with sra and we decided this assert can be ignored now. it made sense a
couple years ago but doesn't now that we are less concerned about fully hiding
the fact that we are compiling to JS.

       assert(enclosingClass.isNative &&
              !element.fixedBackendName.contains(r'$'));