Partial support to IDBKey to Dart conversions.

Source/WebCore/bindings/dart/custom/DartIDBKeyCustom.cpp

 // Copyright 2011, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //    * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //    * Redistributions in binary form must reproduce the above
@@ skipping 44 matching lines @@
 
     if (Dart_IsList(handle)) {
         // FIXME: Support Array case.
         exception = DART_UNIMPLEMENTED_EXCEPTION();
         return 0;
     }
 
     return IDBKey::createInvalid();
 }
 
-Dart_Handle DartIDBKey::toDart(IDBKey*)
+Dart_Handle DartIDBKey::toDart(IDBKey* key)
 {
-    DART_UNIMPLEMENTED();
-    return 0;
+    if (!key)
+        return Dart_Null();
+
+    switch (key->type()) {
+    case IDBKey::InvalidType:
+    case IDBKey::MinType:
+        ASSERT_NOT_REACHED();
+        return Dart_Null();
+    case IDBKey::NumberType:
+        return DartUtilities::doubleToDart(key->number());
+    case IDBKey::StringType:
+        return DartUtilities::stringToDart(key->string());
+    case IDBKey::DateType:
+        // FIXME: support Date.
+        return Dart_Null();
+    case IDBKey::ArrayType:
+        // FIXME: support Array.
+        return Dart_Null();
+    }
+
+    ASSERT_NOT_REACHED();
+    return Dart_Null();
 }
 
 }
 
 #endif // ENABLE(INDEXED_DATABASE)