Emit the type test support code to the right output unit.

sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart

Index: sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart b/sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart
index 8733590ed263b5ee00b7ebc00161ac5db0f8e590..87a5036cdf2112d988a24e26cb6ee01d2ecb8fa7 100644
--- a/sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_emitter/type_test_emitter.dart
@@ -276,13 +276,18 @@ class TypeTestEmitter extends CodeEmitterHelper {
     }
   }
 
-  void emitRuntimeTypeSupport(CodeBuffer buffer) {
+  void emitRuntimeTypeSupport(CodeBuffer buffer, OutputUnit outputUnit) {
     task.addComment('Runtime type support', buffer);
     RuntimeTypes rti = backend.rti;
     TypeChecks typeChecks = rti.requiredChecks;
 
     // Add checks to the constructors of instantiated classes.
+    // TODO(sigurdm): We should avoid running through this list for each
+    // output unit.
     for (ClassElement cls in typeChecks) {
+      OutputUnit destination =
+          compiler.deferredLoadTask.outputUnitForElement(cls);
+      if (destination != outputUnit) continue;
       // TODO(9556).  The properties added to 'holder' should be generated
       // directly as properties of the class object, not added later.
       String holder = namer.isolateAccess(backend.getImplementationClass(cls));
@@ -306,12 +311,20 @@ class TypeTestEmitter extends CodeEmitterHelper {
       buffer.write(jsAst.prettyPrint(encoding, compiler));
       buffer.add('$N');
     }
+    if (outputUnit == compiler.deferredLoadTask.mainOutputUnit) {
+      // TODO(sigurdm): These should also be possibly deferred.
+      // They should be handled similarly to constants.
+      // They have 3 dependencies:
+      // 1. The libraries containing the check.
+      // 2. The typedef defining it.
+      // 3. The types involved in the typedef.
+      // TODO(sigurdm): Actually these seems to never be used. Remove them.
+      checkedNonGenericFunctionTypes.forEach(addSignature);
+      checkedGenericFunctionTypes.forEach((_, Set<FunctionType> functionTypes) {
+        functionTypes.forEach(addSignature);
+      });
+    }
 
-    checkedNonGenericFunctionTypes.forEach(addSignature);
-
-    checkedGenericFunctionTypes.forEach((_, Set<FunctionType> functionTypes) {
-      functionTypes.forEach(addSignature);
-    });
   }
 
   /**