JS tree shaking for incremental builds.

compiler/lib/implementation/rtt.js

Index: compiler/lib/implementation/rtt.js
diff --git a/compiler/lib/implementation/rtt.js b/compiler/lib/implementation/rtt.js
index 83179d3dfa46193a18563e04bcd62f1eaa1ee3dc..daea1603a37a7ad39eb8f5847f152b6ffefd17c6 100644
--- a/compiler/lib/implementation/rtt.js
+++ b/compiler/lib/implementation/rtt.js
@@ -208,19 +208,16 @@ RTT.getTypeArgsFor = function(o, classkey) {
 // Base types for runtime type information
 
 /** @type {!RTT} */
-RTT.objectType = new RTT($cls('Object'));
-RTT.objectType.implementedBy = function(o) {return true};
-RTT.objectType.implementedByType = function(o) {return true};
-
-/** @type {!RTT} */
-RTT.dynamicType = new RTT($cls('Dynamic'));
-RTT.dynamicType.implementedBy = function(o) {return true};
-RTT.dynamicType.implementedByType = function(o) {return true};
+function ImplementsAll(name) {
+  RTT.call(this,name);
+}
+$inherits(ImplementsAll,RTT);
+ImplementsAll.prototype.implementedBy = function(o) {return true};
+ImplementsAll.prototype.implementedByType = function(o) {return true};
 
-/** @type {!RTT} */
-RTT.placeholderType = new RTT($cls('::'));
-RTT.placeholderType.implementedBy = function(o) {return true};
-RTT.placeholderType.implementedByType = function(o) {return true};
+RTT.objectType = new ImplementsAll($cls('Object'));
+RTT.dynamicType = new ImplementsAll($cls('Dynamic')); 
+RTT.placeholderType = new ImplementsAll($cls('::'));
 
 /**
  * Checks that a value is assignable to an expected type, and either returns that