keep mixin and interface implementation info at runtime

lib/runtime/dart/_interceptors.js

Index: lib/runtime/dart/_interceptors.js
diff --git a/lib/runtime/dart/_interceptors.js b/lib/runtime/dart/_interceptors.js
index 7cf7217cedc0817c11d004db67fc7eb272b983eb..90dec002d8202516d7b0b7486ef5fb44455c513d 100644
--- a/lib/runtime/dart/_interceptors.js
+++ b/lib/runtime/dart/_interceptors.js
@@ -345,6 +345,7 @@ var _interceptors;
         return new _internal.IterableMixinWorkaround().asMapList(this);
       }
     }
+    JSArray[dart.implements] = [core.List$(E), JSIndexable];
     dart.defineNamedConstructor(JSArray, 'fixed');
     dart.defineNamedConstructor(JSArray, 'emptyGrowable');
     dart.defineNamedConstructor(JSArray, 'growable');
@@ -357,6 +358,7 @@ var _interceptors;
   let JSMutableArray$ = dart.generic(function(E) {
     class JSMutableArray extends JSArray$(E) {
     }
+    JSMutableArray[dart.implements] = [JSMutableIndexable];
     return JSMutableArray;
   });
   let JSMutableArray = JSMutableArray$(dart.dynamic);
@@ -687,6 +689,7 @@ var _interceptors;
       return core.num;
     }
   }
+  JSNumber[dart.implements] = [core.num];
   JSNumber._MIN_INT32 = -2147483648;
   JSNumber._MAX_INT32 = 2147483647;
   let _bitCount = Symbol('_bitCount');
@@ -751,6 +754,7 @@ var _interceptors;
       return dart.as(~this >>> 0, core.int);
     }
   }
+  JSInt[dart.implements] = [core.int, core.double];
   class JSDouble extends JSNumber {
     JSDouble() {
       super.JSNumber();
@@ -759,6 +763,7 @@ var _interceptors;
       return core.double;
     }
   }
+  JSDouble[dart.implements] = [core.double];
   class JSPositiveInt extends JSInt {
   }
   class JSUInt32 extends JSPositiveInt {
@@ -1186,6 +1191,7 @@ var _interceptors;
       return this[index];
     }
   }
+  JSString[dart.implements] = [core.String, JSIndexable];
   let _string = Symbol('_string');
   class _CodeUnits extends _internal.UnmodifiableListBase$(core.int) {
     _CodeUnits(string$) {
@@ -1337,6 +1343,7 @@ var _interceptors;
       return core.bool;
     }
   }
+  JSBool[dart.implements] = [core.bool];
   class JSNull extends Interceptor {
     JSNull() {
       super.Interceptor();
@@ -1357,6 +1364,7 @@ var _interceptors;
       return super.noSuchMethod(invocation);
     }
   }
+  JSNull[dart.implements] = [core.Null];
   class JSIndexable extends core.Object {
   }
   class JSMutableIndexable extends JSIndexable {
@@ -1374,6 +1382,7 @@ var _interceptors;
       return JSObject;
     }
   }
+  JavaScriptObject[dart.implements] = [JSObject];
   class PlainJavaScriptObject extends JavaScriptObject {
     PlainJavaScriptObject() {
       super.JavaScriptObject();