- Remove Isolate::Flags structure and store flags directly in isolate.

runtime/lib/isolate.cc

Index: runtime/lib/isolate.cc
diff --git a/runtime/lib/isolate.cc b/runtime/lib/isolate.cc
index f6d248a145b460d078e65ba91c3fe47df2506a80..fb51c07afed8253423d5304972b306231f6c08b0 100644
--- a/runtime/lib/isolate.cc
+++ b/runtime/lib/isolate.cc
@@ -151,8 +151,8 @@ class SpawnIsolateTask : public ThreadPool::Task {
       return;
     }
 
-    Dart_IsolateFlags api_flags;
-    state_->isolate_flags()->CopyTo(&api_flags);
+    // Make a copy of the state's isolate flags and hand it to the callback.
+    Dart_IsolateFlags api_flags = *(state_->isolate_flags());
 
     Isolate* isolate = reinterpret_cast<Isolate*>(
         (callback)(state_->script_url(),
@@ -391,7 +391,10 @@ DEFINE_NATIVE_ENTRY(Isolate_spawnUri, 12) {
   // If we were passed a value then override the default flags state for
   // checked mode.
   if (!checked.IsNull()) {
-    state->isolate_flags()->set_checked(checked.value());
+    bool val = checked.value();
+    Dart_IsolateFlags* flags = state->isolate_flags();
+    flags->enable_asserts = val;
+    flags->enable_type_checks = val;
   }
 
   ThreadPool::Task* spawn_task = new SpawnIsolateTask(state);