Fix strong mode errors in SVG

tools/dom/scripts/systemhtml.py

Index: tools/dom/scripts/systemhtml.py
diff --git a/tools/dom/scripts/systemhtml.py b/tools/dom/scripts/systemhtml.py
index 64351a8ac06ebeadf1d99f8a60baba4c11d3cdba..62896ba9ebc8c99b3c9c9fb7260fee2a21951b92 100644
--- a/tools/dom/scripts/systemhtml.py
+++ b/tools/dom/scripts/systemhtml.py
@@ -19,6 +19,22 @@ _logger = logging.getLogger('systemhtml')
 HTML_LIBRARY_NAMES = ['html', 'indexed_db', 'svg',
                       'web_audio', 'web_gl', 'web_sql']
 
+# 
+# The following two sets let us avoid shadowing fields with properties.
+# This information could be derived from the IDL files but would require
+# a significant refactor to compute accurately. Instead we manually compute
+# these sets based on manual triage ofstrong mode errors.

[Alan Knight, 2016/04/21 19:37:07]

extreme nit: typo in ofstrong

[Jacob, 2016/04/21 19:42:41]

it isdone

+_force_property_members = monitored.Set('systemhtml._force_property_members', [
+    'Element.outerHtml',
+    'Element.isContentEditable',
+    'AudioContext.createGain',
+    'AudioContext.createScriptProcessor',
+    ])
+_safe_to_ignore_shadowing_members = monitored.Set('systemhtml._safe_to_ignore_shadowing_members', [
+    'SVGElement.tabIndex',
+    'SVGStyleElement.title',
+    ])
+
 _js_custom_members = monitored.Set('systemhtml._js_custom_members', [
     'AudioBufferSourceNode.start',
     'AudioBufferSourceNode.stop',
@@ -895,8 +911,13 @@ class Dart2JSBackend(HtmlDartGenerator):
     #  is renamed.
     (super_attribute, super_attribute_interface) = self._FindShadowedAttribute(
         attribute)
+    if self._ForcePropertyMember(html_name):
+      self._members_emitter.Emit('\n  // Using property as subclass shadows.');
+      self._AddAttributeUsingProperties(attribute, html_name, read_only)
+      return
+
     if super_attribute:
-      if read_only:
+      if read_only or self._SafeToIgnoreShadowingMember(html_name):
         if attribute.type.id == super_attribute.type.id:
           # Compatible attribute, use the superclass property.  This works
           # because JavaScript will do its own dynamic dispatch.
@@ -1161,6 +1182,14 @@ class Dart2JSBackend(HtmlDartGenerator):
     member_name = '%s.%s' % (self._interface.doc_js_name, member_name)
     return member_name in _js_custom_members
 
+  def _ForcePropertyMember(self, member_name):
+    member_name = '%s.%s' % (self._interface.doc_js_name, member_name)
+    return member_name in _force_property_members
+
+  def _SafeToIgnoreShadowingMember(self, member_name):
+    member_name = '%s.%s' % (self._interface.doc_js_name, member_name)
+    return member_name in _safe_to_ignore_shadowing_members
+
   def _RenamingAnnotation(self, idl_name, member_name):
     if member_name != idl_name:
       return  "@JSName('%s')\n  " % idl_name