Adding ElementEventStream.capture

tools/dom/templates/html/impl/impl_Element.darttemplate

Index: tools/dom/templates/html/impl/impl_Element.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_Element.darttemplate b/tools/dom/templates/html/impl/impl_Element.darttemplate
index d258a6199c479f444bc03b098285927c9fc27d6b..534aeb856573fb428452cceb872e9f2ed88524d9 100644
--- a/tools/dom/templates/html/impl/impl_Element.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Element.darttemplate
@@ -584,7 +584,7 @@ $(ANNOTATIONS)abstract class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   ElementList querySelectorAll(String selectors) =>
     new _FrozenElementList._wrap(_querySelectorAll(selectors));
 
-  /** 
+  /**
    * Alias for [querySelector]. Note this function is deprecated because its
    * semantics will be changing in the future.
    */
@@ -593,7 +593,7 @@ $(ANNOTATIONS)abstract class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   @Experimental()
   Element query(String relativeSelectors) => querySelector(relativeSelectors);
 
-  /** 
+  /**
    * Alias for [querySelectorAll]. Note this function is deprecated because its
    * semantics will be changing in the future.
    */
@@ -1380,6 +1380,12 @@ $endif
     _innerHtml = html;
   }
 
+  /**
+   * This is an ease-of-use accessor for event streams which should only be
+   * used when an explicit accessor is not available.
+   */
+  ElementEvents get on => new ElementEvents(this);
+
 $!MEMBERS
 }