Fix for issue 23547, return an proper ApiError instead of a string when we report outstanding typed…

runtime/vm/dart_api_state.h

Index: runtime/vm/dart_api_state.h
diff --git a/runtime/vm/dart_api_state.h b/runtime/vm/dart_api_state.h
index 31be5fb405d46aebfaa82fd026eba213001ed57e..34b9f9a0995c0e380d888ee3ef39d4106c4392cd 100644
--- a/runtime/vm/dart_api_state.h
+++ b/runtime/vm/dart_api_state.h
@@ -818,10 +818,11 @@ class ApiState {
 
   void SetupAcquiredError() {
     ASSERT(acquired_error_ == NULL);
-    acquired_error_ = persistent_handles().AllocateHandle();
-    acquired_error_->set_raw(
+    const String& msg = String::Handle(
         String::New("Internal Dart data pointers have been acquired, "
                     "please release them using Dart_TypedDataReleaseData."));
+    acquired_error_ = persistent_handles().AllocateHandle();
+    acquired_error_->set_raw(ApiError::New(msg));
   }
 
   PersistentHandle* AcquiredError() const {