Track fields which are known to be always set to integer constants

lib/compiler/implementation/ssa/codegen.dart

Index: lib/compiler/implementation/ssa/codegen.dart
diff --git a/lib/compiler/implementation/ssa/codegen.dart b/lib/compiler/implementation/ssa/codegen.dart
index 779ff35e47f1be5794f37fb16b754a5035c5127c..540818d4e4959ae50855f3fb45b8bef852fb4cab 100644
--- a/lib/compiler/implementation/ssa/codegen.dart
+++ b/lib/compiler/implementation/ssa/codegen.dart
@@ -1738,7 +1738,9 @@ class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
       buffer.add(name);
       Type type = node.receiver.propagatedType.computeType(compiler);
       if (type != null) {
-        world.registerFieldSetter(node.element.name, type);
+        world.registerFieldSetter(node.element.name,
+                                  type,
+                                  node.value.isInteger());
       }
     } else {
       declareInstruction(node.receiver);
@@ -1768,6 +1770,17 @@ class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
   }
 
   visitForeignNew(HForeignNew node) {
+    var i = 0;
+    node.element.forEachInstanceField(
+      includeBackendMembers: true,
+      includeSuperMembers: true,
+      f: (ClassElement enclosingClass, Element member) {
+        world.registerFieldInitializer(member.name,
+                                       enclosingClass.computeType(compiler),
+                                       node.inputs[i].isInteger());
+
+        i++;
+      });
     String jsClassReference = compiler.namer.isolateAccess(node.element);
     beginExpression(JSPrecedence.MEMBER_PRECEDENCE);
     buffer.add('new $jsClassReference(');