Refine types of EventTarget

sdk/lib/html/scripts/generator.py

Index: sdk/lib/html/scripts/generator.py
diff --git a/sdk/lib/html/scripts/generator.py b/sdk/lib/html/scripts/generator.py
index 1ba1bcd576fee9b3c010633cb448b1bcde7989b2..703e14889b8aa802134f6bafabc43720d8cc53d4 100644
--- a/sdk/lib/html/scripts/generator.py
+++ b/sdk/lib/html/scripts/generator.py
@@ -594,6 +594,7 @@ def FindConversion(idl_type, direction, interface, member):
 #
 #   INTERFACE.MEMBER: annotations for member.
 #   +TYPE:            add annotations only if there are member annotations.
+#   -TYPE:            add annotations only if there are no member annotations.
 #   TYPE:             add regardless of member annotations.
 
 dart2js_annotations = {
@@ -615,10 +616,26 @@ dart2js_annotations = {
     'DOMWindow.openDatabase': "@Creates('Database') @Creates('DatabaseSync')",
 
     # Cross-frame windows are EventTargets.
-    'EventTarget':
-      #"@Creates('Null') @Returns('EventTarget|=Object')",
+    '-EventTarget':
       "@Creates('EventTarget|=Object') @Returns('EventTarget|=Object')",
 
+    # To be in callback with the browser-created Event, we had to have called
+    # addEventListener on the target, so we avoid
+    'Event.currentTarget':
+        "@Creates('Null') @Returns('EventTarget|=Object')",
+
+    # Only nodes in the DOM bubble and have target !== currentTarget.
+    'Event.target':
+        "@Creates('Node') @Returns('EventTarget|=Object')",
+
+    'MouseEvent.relatedTarget':
+        "@Creates('Node') @Returns('EventTarget|=Object')",
+
+    # Touch targets are Elements in a Document, or the Document.
+    'Touch.target':
+        "@Creates('Element|Document') @Returns('Element|Document')",
+
+
     'FileReader.result': "@Creates('String|ArrayBuffer|Null')",
 
     # Rather than have the result of an IDBRequest as a union over all possible
@@ -687,6 +704,9 @@ def FindAnnotations(idl_type, interface_name, member_name):
       return ann2 + ' ' + ann1
     return ann1
 
+  ann2 = dart2js_annotations.get('-' + idl_type)
+  if ann2:
+    return ann2
   ann2 = dart2js_annotations.get(idl_type)
   return ann2