Set main procedure for Program.

pkg/front_end/lib/src/incremental_kernel_generator_impl.dart

Index: pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
diff --git a/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart b/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
index d75a0fc7d25e13d750e189cd41b3b71caadb7d22..da49e55bfcf118a16a04dff9224505b51f1b8b0e 100644
--- a/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
+++ b/pkg/front_end/lib/src/incremental_kernel_generator_impl.dart
@@ -135,6 +135,16 @@ class IncrementalKernelGeneratorImpl implements IncrementalKernelGenerator {
       // contents to compute signatures (not just API parts). So, every library
       // that imports a changed one, is affected.
 
+      // Set the main procedure.
+      for (var library in program.libraries) {
+        if (library.fileUri == _entryPoint.toString()) {
+          program.mainMethod = library.procedures.firstWhere(
+              (procedure) => procedure.name.name == 'main',
+              orElse: () => null);
+          break;
+        }
+      }
+
       return new DeltaProgram(program);
     });
   }