Introduce the Error object class in the vm. It represents all of the

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 3167)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -39,13 +39,13 @@
   do {                                                                        \
     const Object& tmp = Object::Handle(Api::UnwrapHandle((dart_handle)));     \
     if (tmp.IsNull()) {                                                       \
-      return Api::Error("%s expects argument '%s' to be non-null.",           \
-                        CURRENT_FUNC, #dart_handle);                          \
-    } else if (tmp.IsApiError()) {                                            \
+      return Api::NewError("%s expects argument '%s' to be non-null.",        \
+                           CURRENT_FUNC, #dart_handle);                       \
+    } else if (tmp.IsError()) {                                               \
       return dart_handle;                                                     \
     } else {                                                                  \
-      return Api::Error("%s expects argument '%s' to be of type %s.",         \
-                        CURRENT_FUNC, #dart_handle, #Type);                   \
+      return Api::NewError("%s expects argument '%s' to be of type %s.",      \
+                           CURRENT_FUNC, #dart_handle, #Type);                \
     }                                                                         \
   } while (0)
 
@@ -83,7 +83,7 @@
   // may get deallocated when we return back from the Dart API call.
   const String& error = String::Handle(
       Isolate::Current()->object_store()->sticky_error());
-  const Object& obj = Object::Handle(ApiError::New(error));
+  const Object& obj = Object::Handle(LanguageError::New(error));
   *handle = Api::NewLocalHandle(obj);
 }
 
@@ -103,11 +103,7 @@
     const Array& kNoArgumentNames = Array::Handle();
     const Instance& retval = Instance::Handle(
         DartEntry::InvokeStatic(function, args, kNoArgumentNames));
-    if (retval.IsUnhandledException()) {
-      *result = Api::ErrorFromException(retval);
-    } else {
-      *result = Api::NewLocalHandle(retval);
-    }
+    *result = Api::NewLocalHandle(retval);
   } else {
     SetupErrorResult(result);
   }
@@ -131,11 +127,7 @@
     const Array& kNoArgumentNames = Array::Handle();
     const Instance& retval = Instance::Handle(
         DartEntry::InvokeDynamic(receiver, function, args, kNoArgumentNames));
-    if (retval.IsUnhandledException()) {
-      *result = Api::ErrorFromException(retval);
-    } else {
-      *result = Api::NewLocalHandle(retval);
-    }
+    *result = Api::NewLocalHandle(retval);
   } else {
     SetupErrorResult(result);
   }
@@ -218,7 +210,7 @@
 }
 
 
-Dart_Handle Api::Error(const char* format, ...) {
+Dart_Handle Api::NewError(const char* format, ...) {
   DARTSCOPE_NOCHECKS(Isolate::Current());
 
   va_list args;
@@ -238,21 +230,6 @@
 }
 
 
-Dart_Handle Api::ErrorFromException(const Object& obj) {
-  DARTSCOPE_NOCHECKS(Isolate::Current());
-
-  ASSERT(obj.IsUnhandledException());
-  if (obj.IsUnhandledException()) {
-    UnhandledException& uhe = UnhandledException::Handle();
-    uhe ^= obj.raw();
-    const Object& error = Object::Handle(ApiError::New(uhe));
-    return Api::NewLocalHandle(error);
-  } else {
-    return Api::Error("Internal error: expected obj.IsUnhandledException().");
-  }
-}
-
-
 Dart_Handle Api::Null() {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
@@ -311,7 +288,7 @@
 DART_EXPORT bool Dart_IsError(Dart_Handle handle) {
   DARTSCOPE(Isolate::Current());
   const Object& obj = Object::Handle(Api::UnwrapHandle(handle));
-  return obj.IsApiError();
+  return obj.IsError();
 }
 
 
@@ -320,16 +297,16 @@
   const Instance& exception = Instance::Handle(uhe.exception());
   Object& strtmp = Object::Handle(DartLibraryCalls::ToString(exception));
   const char* exc_str =
-      "<Received exception while converting exception to string>";
-  if (!strtmp.IsUnhandledException()) {
+      "<Received error while converting exception to string>";
+  if (!strtmp.IsError()) {
     exc_str = strtmp.ToCString();
   }
 
   const Instance& stack = Instance::Handle(uhe.stacktrace());
   strtmp = DartLibraryCalls::ToString(stack);
   const char* stack_str =
-      "<Received exception while converting stack trace to string>";
-  if (!strtmp.IsUnhandledException()) {
+      "<Received error while converting stack trace to string>";
+  if (!strtmp.IsError()) {
     stack_str = strtmp.ToCString();
   }
 
@@ -347,29 +324,36 @@
   DARTSCOPE(Isolate::Current());
 
   const Object& obj = Object::Handle(Api::UnwrapHandle(handle));
-  if (!obj.IsApiError()) {
+  if (!obj.IsError()) {
     return "";
   }
-  ApiError& failure = ApiError::Handle();
-  failure ^= obj.raw();
-  const Object& data = Object::Handle(failure.data());
-  if (data.IsString()) {
-    // Simple error message.
-    String& message = String::Handle();
-    message ^= failure.data();
+  if (obj.IsApiError()) {
+    ApiError& error = ApiError::Handle();
+    error ^= obj.raw();
+    const String& message = String::Handle(error.message());
     const char* msg = message.ToCString();
     intptr_t len = strlen(msg) + 1;
     char* msg_copy = reinterpret_cast<char*>(Api::Allocate(len));
     strncpy(msg_copy, msg, len);
     return msg_copy;
-
-  } else if (data.IsUnhandledException()) {
-    UnhandledException& uhe = UnhandledException::Handle();
-    uhe ^= data.raw();
-    return MakeUnhandledExceptionCString(uhe);
-
+  } else if (obj.IsLanguageError()) {
+    LanguageError& error = LanguageError::Handle();
+    error ^= obj.raw();
+    const String& message = String::Handle(error.message());
+    const char* msg = message.ToCString();
+    intptr_t len = strlen(msg) + 1;
+    char* msg_copy = reinterpret_cast<char*>(Api::Allocate(len));
+    strncpy(msg_copy, msg, len);
+    return msg_copy;
+  } else if (obj.IsUnhandledException()) {
+    UnhandledException& error = UnhandledException::Handle();
+    error ^= obj.raw();
+    return MakeUnhandledExceptionCString(error);
+  } else if (obj.IsUnwindError()) {
+    UNIMPLEMENTED();
+    return "<unimplemented>;";
   } else {
-    return "<Internal error in Dart_GetError: malformed error handle>";
+    return "<Internal error in Dart_GetError: unexpected error type>";
   }
 }
 
@@ -377,31 +361,22 @@
 DART_EXPORT bool Dart_ErrorHasException(Dart_Handle handle) {
   DARTSCOPE(Isolate::Current());
   const Object& obj = Object::Handle(Api::UnwrapHandle(handle));
-  if (obj.IsApiError()) {
-    const ApiError& error = ApiError::CheckedHandle(obj.raw());
-    const Object& data = Object::Handle(error.data());
-    return data.IsUnhandledException();
-  }
-  return false;
+  return obj.IsUnhandledException();
 }
 
 
 DART_EXPORT Dart_Handle Dart_ErrorGetException(Dart_Handle handle) {
   DARTSCOPE(Isolate::Current());
   const Object& obj = Object::Handle(Api::UnwrapHandle(handle));
-  if (obj.IsApiError()) {
-    const ApiError& error = ApiError::CheckedHandle(obj.raw());
-    const Object& data = Object::Handle(error.data());
-    if (data.IsUnhandledException()) {
-      const UnhandledException& unhandled = UnhandledException::Handle(
-          reinterpret_cast<RawUnhandledException*>(data.raw()));
-      const Object& exception = Object::Handle(unhandled.exception());
-      return Api::NewLocalHandle(exception);
-    } else {
-      return Api::Error("This error is not an unhandled exception error.");
-    }
+  if (obj.IsUnhandledException()) {
+    UnhandledException& error = UnhandledException::Handle();
+    error ^= obj.raw();
+    const Object& exception = Object::Handle(error.exception());
+    return Api::NewLocalHandle(exception);
+  } else if (obj.IsError()) {
+    return Api::NewError("This error is not an unhandled exception error.");
   } else {
-    return Api::Error("Can only get exceptions from error handles.");
+    return Api::NewError("Can only get exceptions from error handles.");
   }
 }
 
@@ -409,25 +384,20 @@
 DART_EXPORT Dart_Handle Dart_ErrorGetStacktrace(Dart_Handle handle) {
   DARTSCOPE(Isolate::Current());
   const Object& obj = Object::Handle(Api::UnwrapHandle(handle));
-  if (obj.IsApiError()) {
-    ApiError& failure = ApiError::Handle();
-    failure ^= obj.raw();
-    const Object& data = Object::Handle(failure.data());
-    if (data.IsUnhandledException()) {
-      const UnhandledException& unhandled = UnhandledException::Handle(
-          reinterpret_cast<RawUnhandledException*>(data.raw()));
-      const Object& stacktrace = Object::Handle(unhandled.stacktrace());
-      return Api::NewLocalHandle(stacktrace);
-    } else {
-      return Api::Error("This error is not an unhandled exception error.");
-    }
+  if (obj.IsUnhandledException()) {
+    UnhandledException& error = UnhandledException::Handle();
+    error ^= obj.raw();
+    const Object& stacktrace = Object::Handle(error.stacktrace());
+    return Api::NewLocalHandle(stacktrace);
+  } else if (obj.IsError()) {
+    return Api::NewError("This error is not an unhandled exception error.");
   } else {
-    return Api::Error("Can only get stacktraces from error handles.");
+    return Api::NewError("Can only get stacktraces from error handles.");
   }
 }
 
 
-// TODO(turnidge): This clones Api::Error.  I need to use va_copy to
+// TODO(turnidge): This clones Api::NewError.  I need to use va_copy to
 // fix this but not sure if it available on all of our builds.
 DART_EXPORT Dart_Handle Dart_Error(const char* format, ...) {
   DARTSCOPE(Isolate::Current());
@@ -469,9 +439,6 @@
     Instance& receiver = Instance::Handle();
     receiver ^= obj.raw();
     result = DartLibraryCalls::ToString(receiver);
-    if (result.IsUnhandledException()) {
-      return Api::ErrorFromException(result);
-    }
   } else {
     // This is a VM internal object. Call the C++ method of printing.
     result = String::New(obj.ToCString());
@@ -637,17 +604,17 @@
   DARTSCOPE(isolate);
   TIMERSCOPE(time_creating_snapshot);
   if (buffer == NULL) {
-    return Api::Error("%s expects argument 'buffer' to be non-null.",
-                      CURRENT_FUNC);
+    return Api::NewError("%s expects argument 'buffer' to be non-null.",
+                         CURRENT_FUNC);
   }
   if (size == NULL) {
-    return Api::Error("%s expects argument 'size' to be non-null.",
-                      CURRENT_FUNC);
+    return Api::NewError("%s expects argument 'size' to be non-null.",
+                         CURRENT_FUNC);
   }
   const char* msg = CheckIsolateState(isolate,
                                       ClassFinalizer::kGeneratingSnapshot);
   if (msg != NULL) {
-    return Api::Error(msg);
+    return Api::NewError(msg);
   }
   // Since this is only a snapshot the root library should not be set.
   isolate->object_store()->set_root_library(Library::Handle());
@@ -664,20 +631,21 @@
   DARTSCOPE(isolate);
   TIMERSCOPE(time_creating_snapshot);
   if (buffer == NULL) {
-    return Api::Error("%s expects argument 'buffer' to be non-null.",
-                      CURRENT_FUNC);
+    return Api::NewError("%s expects argument 'buffer' to be non-null.",
+                         CURRENT_FUNC);
   }
   if (size == NULL) {
-    return Api::Error("%s expects argument 'size' to be non-null.",
-                      CURRENT_FUNC);
+    return Api::NewError("%s expects argument 'size' to be non-null.",
+                         CURRENT_FUNC);
   }
   const char* msg = CheckIsolateState(isolate);
   if (msg != NULL) {
-    return Api::Error(msg);
+    return Api::NewError(msg);
   }
   Library& library = Library::Handle(isolate->object_store()->root_library());
   if (library.IsNull()) {
-    return Api::Error("%s expects the isolate to have a script loaded in it.",
+    return
+        Api::NewError("%s expects the isolate to have a script loaded in it.",
                       CURRENT_FUNC);
   }
   ScriptSnapshotWriter writer(buffer, ApiAllocator);
@@ -721,8 +689,8 @@
   isolate->set_long_jump_base(&jump);
   if (setjmp(*jump.Set()) == 0) {
     const Object& obj = Object::Handle(isolate->StandardRunLoop());
-    if (obj.IsUnhandledException()) {
-      result = Api::ErrorFromException(obj);
+    if (obj.IsError()) {
+      result = Api::NewLocalHandle(obj);
     } else {
       ASSERT(obj.IsNull());
       result = Api::Success();
@@ -758,8 +726,8 @@
       Object::Handle(DartLibraryCalls::HandleMessage(dest_port_id,
                                                      reply_port_id,
                                                      msg));
-  if (result.IsUnhandledException()) {
-    return Api::ErrorFromException(result);
+  if (result.IsError()) {
+    return Api::NewLocalHandle(result);
   }
   ASSERT(result.IsNull());
   return Api::Success();
@@ -913,10 +881,10 @@
     b ^= result.raw();
     *value = b.value();
     return Api::Success();
-  } else if (result.IsUnhandledException()) {
-    return Api::ErrorFromException(result);
+  } else if (result.IsError()) {
+    return Api::NewLocalHandle(result);
   } else {
-    return Api::Error("Expected boolean result from ==");
+    return Api::NewError("Expected boolean result from ==");
   }
 }
 
@@ -931,7 +899,7 @@
   DARTSCOPE(isolate);
   const Class& cls = Class::CheckedHandle(Api::UnwrapHandle(clazz));
   if (cls.IsNull()) {
-    return Api::Error("instanceof check against null class");
+    return Api::NewError("instanceof check against null class");
   }
   const Object& obj = Object::Handle(Api::UnwrapHandle(object));
   Instance& instance = Instance::Handle();
@@ -939,7 +907,7 @@
   // Finalize all classes.
   const char* msg = CheckIsolateState(isolate);
   if (msg != NULL) {
-    return Api::Error(msg);
+    return Api::NewError(msg);
   }
   const Type& type = Type::Handle(Type::NewNonParameterizedType(cls));
   *value = instance.IsInstanceOf(type, TypeArguments::Handle());
@@ -1043,8 +1011,8 @@
       return Api::Success();
     }
   }
-  return Api::Error("%s: Integer %s cannot be represented as an int64_t.",
-                    CURRENT_FUNC, int_obj.ToCString());
+  return Api::NewError("%s: Integer %s cannot be represented as an int64_t.",
+                       CURRENT_FUNC, int_obj.ToCString());
 }
 
 
@@ -1069,8 +1037,8 @@
       return Api::Success();
     }
   }
-  return Api::Error("%s: Integer %s cannot be represented as a uint64_t.",
-                    CURRENT_FUNC, int_obj.ToCString());
+  return Api::NewError("%s: Integer %s cannot be represented as a uint64_t.",
+                       CURRENT_FUNC, int_obj.ToCString());
 }
 
 
@@ -1197,7 +1165,7 @@
     *len = string_obj.Length();
     return Api::Success();
   }
-  return Api::Error("Object is not a String");
+  return Api::NewError("Object is not a String");
 }
 
 
@@ -1250,12 +1218,13 @@
     RETURN_TYPE_ERROR(object, String);
   }
   if (!str.IsExternal()) {
-    return Api::Error("%s expects argument 'object' to be an external String.",
+    return
+        Api::NewError("%s expects argument 'object' to be an external String.",
                       CURRENT_FUNC);
   }
   if (peer == NULL) {
-    return Api::Error("%s expects argument 'peer' to be non-null.",
-                      CURRENT_FUNC);
+    return Api::NewError("%s expects argument 'peer' to be non-null.",
+                         CURRENT_FUNC);
   }
   *peer = str.GetPeer();
   return Api::Success();
@@ -1313,9 +1282,9 @@
       return Api::Success();
     }
   }
-  return Api::Error(obj.IsString()
-                    ? "Object is not a String8"
-                    : "Object is not a String");
+  return Api::NewError(obj.IsString()
+                       ? "Object is not a String8"
+                       : "Object is not a String");
 }
 
 
@@ -1337,9 +1306,9 @@
       return Api::Success();
     }
   }
-  return Api::Error(obj.IsString()
-                    ? "Object is not a String16"
-                    : "Object is not a String");
+  return Api::NewError(obj.IsString()
+                       ? "Object is not a String16"
+                       : "Object is not a String");
 }
 
 
@@ -1359,7 +1328,7 @@
     *length = copy_len;
     return Api::Success();
   }
-  return Api::Error("Object is not a String");
+  return Api::NewError("Object is not a String");
 }
 
 
@@ -1372,14 +1341,14 @@
     intptr_t string_length = strlen(string_value);
     char* res = reinterpret_cast<char*>(Api::Allocate(string_length + 1));
     if (res == NULL) {
-      return Api::Error("Unable to allocate memory");
+      return Api::NewError("Unable to allocate memory");
     }
     strncpy(res, string_value, string_length + 1);
     ASSERT(res[string_length] == '\0');
     *result = res;
     return Api::Success();
   }
-  return Api::Error("Object is not a String");
+  return Api::NewError("Object is not a String");
 }
 
 
@@ -1458,13 +1427,14 @@
           if (BigintOperations::FitsIntoInt64(bigint)) {
             *len = BigintOperations::ToInt64(bigint);
           } else {
-            result = Api::Error("Length of List object is greater than the "
-                                "maximum value that 'len' parameter can hold");
+            result =
+                Api::NewError("Length of List object is greater than the "
+                              "maximum value that 'len' parameter can hold");
           }
-        } else if (retval.IsUnhandledException()) {
-          result = Api::ErrorFromException(retval);
+        } else if (retval.IsError()) {
+          result = Api::NewLocalHandle(retval);
         } else {
-          result = Api::Error("Length of List object is not an integer");
+          result = Api::NewError("Length of List object is not an integer");
         }
       } else {
         SetupErrorResult(&result);
@@ -1473,7 +1443,7 @@
       return result;
     }
   }
-  return Api::Error("Object does not implement the list inteface");
+  return Api::NewError("Object does not implement the list inteface");
 }
 
 
@@ -1496,8 +1466,8 @@
                                       function,
                                       args,
                                       kNoArgumentNames);
-    if (retval.IsUnhandledException()) {
-      *result = Api::ErrorFromException(retval);
+    if (retval.IsError()) {
+      *result = Api::NewLocalHandle(retval);
     } else {
       *result = Api::Success();
     }
@@ -1521,7 +1491,7 @@
       const Object& element = Object::Handle(array_obj.At(index));
       return Api::NewLocalHandle(element);
     }
-    return Api::Error("Invalid index passed in to access array element");
+    return Api::NewError("Invalid index passed in to access array element");
   }
   // TODO(5526318): Make access to GrowableObjectArray more efficient.
   // Now check and handle a dart object that implements the List interface.
@@ -1542,7 +1512,7 @@
       return Api::NewLocalHandle(element);
     }
   }
-  return Api::Error("Object does not implement the 'List' interface");
+  return Api::NewError("Object does not implement the 'List' interface");
 }
 
 
@@ -1567,8 +1537,8 @@
                                       function,
                                       args,
                                       kNoArgumentNames);
-    if (retval.IsUnhandledException()) {
-      *result = Api::ErrorFromException(retval);
+    if (retval.IsError()) {
+      *result = Api::NewLocalHandle(retval);
     } else {
       *result = Api::Success();
     }
@@ -1587,7 +1557,7 @@
   const Object& obj = Object::Handle(Api::UnwrapHandle(list));
   if (obj.IsArray()) {
     if (obj.IsImmutableArray()) {
-      return Api::Error("Cannot modify immutable array");
+      return Api::NewError("Cannot modify immutable array");
     }
     Array& array_obj = Array::Handle();
     array_obj ^= obj.raw();
@@ -1596,7 +1566,7 @@
       array_obj.SetAt(index, value_obj);
       return Api::Success();
     }
-    return Api::Error("Invalid index passed in to set array element");
+    return Api::NewError("Invalid index passed in to set array element");
   }
   // TODO(5526318): Make access to GrowableObjectArray more efficient.
   // Now check and handle a dart object that implements the List interface.
@@ -1613,7 +1583,7 @@
       return result;
     }
   }
-  return Api::Error("Object does not implement the 'List' interface");
+  return Api::NewError("Object does not implement the 'List' interface");
 }
 
 
@@ -1633,7 +1603,7 @@
       for (int i = 0; i < length; i++) {
         element = array_obj.At(offset + i);
         if (!element.IsInteger()) {
-          return Api::Error("%s expects the argument 'list' to be "
+          return Api::NewError("%s expects the argument 'list' to be "
                             "a List of int", CURRENT_FUNC);
         }
         integer ^= element.raw();
@@ -1644,7 +1614,7 @@
       }
       return Api::Success();
     }
-    return Api::Error("Invalid length passed in to access array elements");
+    return Api::NewError("Invalid length passed in to access array elements");
   }
   // TODO(5526318): Make access to GrowableObjectArray more efficient.
   // Now check and handle a dart object that implements the List interface.
@@ -1664,7 +1634,7 @@
           return result;  // Error condition.
         }
         if (!element.IsInteger()) {
-          return Api::Error("%s expects the argument 'list' to be "
+          return Api::NewError("%s expects the argument 'list' to be "
                             "a List of int", CURRENT_FUNC);
         }
         intobj ^= element.raw();
@@ -1676,7 +1646,7 @@
       return Api::Success();
     }
   }
-  return Api::Error("Object does not implement the 'List' interface");
+  return Api::NewError("Object does not implement the 'List' interface");
 }
 
 
@@ -1689,7 +1659,7 @@
   const Object& obj = Object::Handle(Api::UnwrapHandle(list));
   if (obj.IsArray()) {
     if (obj.IsImmutableArray()) {
-      return Api::Error("Cannot modify immutable array");
+      return Api::NewError("Cannot modify immutable array");
     }
     Array& array_obj = Array::Handle();
     array_obj ^= obj.raw();
@@ -1701,7 +1671,7 @@
       }
       return Api::Success();
     }
-    return Api::Error("Invalid length passed in to set array elements");
+    return Api::NewError("Invalid length passed in to set array elements");
   }
   // TODO(5526318): Make access to GrowableObjectArray more efficient.
   // Now check and handle a dart object that implements the List interface.
@@ -1725,7 +1695,7 @@
       return Api::Success();
     }
   }
-  return Api::Error("Object does not implement the 'List' interface");
+  return Api::NewError("Object does not implement the 'List' interface");
 }
 
 
@@ -1754,11 +1724,7 @@
     const Array& kNoArgumentNames = Array::Handle();
     const Instance& retval = Instance::Handle(
         DartEntry::InvokeClosure(closure, args, kNoArgumentNames));
-    if (retval.IsUnhandledException()) {
-      *result = Api::ErrorFromException(retval);
-    } else {
-      *result = Api::NewLocalHandle(retval);
-    }
+    *result = Api::NewLocalHandle(retval);
   } else {
     SetupErrorResult(result);
   }
@@ -1773,10 +1739,10 @@
   DARTSCOPE(isolate);
   const Object& obj = Object::Handle(Api::UnwrapHandle(closure));
   if (obj.IsNull()) {
-    return Api::Error("Null object passed in to invoke closure");
+    return Api::NewError("Null object passed in to invoke closure");
   }
   if (!obj.IsClosure()) {
-    return Api::Error("Invalid closure passed to invoke closure");
+    return Api::NewError("Invalid closure passed to invoke closure");
   }
   ASSERT(ClassFinalizer::AllClassesFinalized());
 
@@ -1823,14 +1789,14 @@
   // Finalize all classes.
   const char* msg = CheckIsolateState(isolate);
   if (msg != NULL) {
-    return Api::Error(msg);
+    return Api::NewError(msg);
   }
 
   // Now try to resolve and invoke the static function.
   const Library& library =
       Library::CheckedHandle(Api::UnwrapHandle(library_in));
   if (library.IsNull()) {
-    return Api::Error("No library specified");
+    return Api::NewError("No library specified");
   }
   const String& class_name =
       String::CheckedHandle(Api::UnwrapHandle(class_name_in));
@@ -1860,7 +1826,7 @@
       OS::SNPrint(msg, (length + 1), format,
                   class_name.ToCString(), function_name.ToCString());
     }
-    return Api::Error(msg);
+    return Api::NewError(msg);
   }
   Dart_Handle retval;
   GrowableArray<const Object*> dart_arguments(number_of_arguments);
@@ -1883,11 +1849,11 @@
   // Let the resolver figure out the correct target for null receiver.
   // E.g., (null).toString() should execute correctly.
   if (!obj.IsNull() && !obj.IsInstance()) {
-    return Api::Error(
+    return Api::NewError(
         "Invalid receiver (not instance) passed to invoke dynamic");
   }
   if (function_name == NULL) {
-    return Api::Error("Invalid function name specified");
+    return Api::NewError("Invalid function name specified");
   }
   ASSERT(ClassFinalizer::AllClassesFinalized());
 
@@ -1903,7 +1869,7 @@
   if (function.IsNull()) {
     // TODO(5415268): Invoke noSuchMethod instead of failing.
     OS::PrintErr("Unable to find instance function: %s\n", name.ToCString());
-    return Api::Error("Unable to find instance function");
+    return Api::NewError("Unable to find instance function");
   }
   Dart_Handle retval;
   GrowableArray<const Object*> dart_arguments(number_of_arguments);
@@ -1940,10 +1906,10 @@
   const Object& param1 = Object::Handle(Api::UnwrapHandle(clazz));
   const Object& param2 = Object::Handle(Api::UnwrapHandle(field_name));
   if (param1.IsNull() || !param1.IsClass()) {
-    return Api::Error("Invalid class specified");
+    return Api::NewError("Invalid class specified");
   }
   if (param2.IsNull() || !param2.IsString()) {
-    return Api::Error("Invalid field name specified");
+    return Api::NewError("Invalid field name specified");
   }
   Class& cls = Class::Handle();
   cls ^= param1.raw();
@@ -1957,10 +1923,10 @@
     if (!function.IsNull()) {
       return Api::NewLocalHandle(function);
     }
-    return Api::Error("Specified field is not found in the class");
+    return Api::NewError("Specified field is not found in the class");
   }
   if (fld.IsNull()) {
-    return Api::Error("Specified field is not found in the class");
+    return Api::NewError("Specified field is not found in the class");
   }
   return Api::NewLocalHandle(fld);
 }
@@ -1971,7 +1937,7 @@
                                        bool is_getter) {
   const Object& param = Object::Handle(Api::UnwrapHandle(name));
   if (param.IsNull() || !param.IsString()) {
-    return Api::Error("Invalid field name specified");
+    return Api::NewError("Invalid field name specified");
   }
   String& field_name = String::Handle();
   field_name ^= param.raw();
@@ -1982,7 +1948,7 @@
     fld = cls.LookupInstanceField(field_name);
     if (!fld.IsNull()) {
       if (!is_getter && fld.is_final()) {
-        return Api::Error("Cannot set value of final fields");
+        return Api::NewError("Cannot set value of final fields");
       }
       func_name = (is_getter
                    ? Field::GetterName(field_name)
@@ -1990,13 +1956,13 @@
       const Function& function = Function::Handle(
           cls.LookupDynamicFunction(func_name));
       if (function.IsNull()) {
-        return Api::Error("Unable to find accessor function in the class");
+        return Api::NewError("Unable to find accessor function in the class");
       }
       return Api::NewLocalHandle(function);
     }
     cls = cls.SuperClass();
   }
-  return Api::Error("Unable to find field in the class");
+  return Api::NewError("Unable to find field in the class");
 }
 
 
@@ -2038,7 +2004,8 @@
   Field& fld = Field::Handle();
   fld ^= Api::UnwrapHandle(result);
   if (fld.is_final()) {
-    return Api::Error("Specified field is a static final field in the class");
+    return Api::NewError(
+        "Specified field is a static final field in the class");
   }
   const Object& val = Object::Handle(Api::UnwrapHandle(value));
   Instance& instance = Instance::Handle();
@@ -2054,7 +2021,7 @@
   DARTSCOPE(isolate);
   const Object& param = Object::Handle(Api::UnwrapHandle(obj));
   if (param.IsNull() || !param.IsInstance()) {
-    return Api::Error("Invalid object passed in to access instance field");
+    return Api::NewError("Invalid object passed in to access instance field");
   }
   Instance& object = Instance::Handle();
   object ^= param.raw();
@@ -2077,7 +2044,7 @@
   DARTSCOPE(isolate);
   const Object& param = Object::Handle(Api::UnwrapHandle(obj));
   if (param.IsNull() || !param.IsInstance()) {
-    return Api::Error("Invalid object passed in to access instance field");
+    return Api::NewError("Invalid object passed in to access instance field");
   }
   Instance& object = Instance::Handle();
   object ^= param.raw();
@@ -2102,7 +2069,7 @@
   DARTSCOPE(isolate);
   const Object& param = Object::Handle(Api::UnwrapHandle(name));
   if (param.IsNull() || !param.IsString() || field_count <= 0) {
-    return Api::Error(
+    return Api::NewError(
         "Invalid arguments passed to Dart_CreateNativeWrapperClass");
   }
   String& cls_name = String::Handle();
@@ -2111,14 +2078,14 @@
   Library& lib = Library::Handle();
   lib ^= Api::UnwrapHandle(library);
   if (lib.IsNull()) {
-    return Api::Error(
+    return Api::NewError(
         "Invalid arguments passed to Dart_CreateNativeWrapperClass");
   }
   const Class& cls = Class::Handle(Class::NewNativeWrapper(&lib,
                                                            cls_name,
                                                            field_count));
   if (cls.IsNull()) {
-    return Api::Error(
+    return Api::NewError(
         "Unable to create native wrapper class : already exists");
   }
   return Api::NewLocalHandle(cls);
@@ -2131,13 +2098,13 @@
   DARTSCOPE(Isolate::Current());
   const Object& param = Object::Handle(Api::UnwrapHandle(obj));
   if (param.IsNull() || !param.IsInstance()) {
-    return Api::Error(
+    return Api::NewError(
         "Invalid object passed in to access native instance field");
   }
   Instance& object = Instance::Handle();
   object ^= param.raw();
   if (!object.IsValidNativeIndex(index)) {
-    return Api::Error(
+    return Api::NewError(
         "Invalid index passed in to access native instance field");
   }
   *value = object.GetNativeField(index);
@@ -2151,12 +2118,14 @@
   DARTSCOPE(Isolate::Current());
   const Object& param = Object::Handle(Api::UnwrapHandle(obj));
   if (param.IsNull() || !param.IsInstance()) {
-    return Api::Error("Invalid object passed in to set native instance field");
+    return Api::NewError(
+        "Invalid object passed in to set native instance field");
   }
   Instance& object = Instance::Handle();
   object ^= param.raw();
   if (!object.IsValidNativeIndex(index)) {
-    return Api::Error("Invalid index passed in to set native instance field");
+    return Api::NewError(
+        "Invalid index passed in to set native instance field");
   }
   object.SetNativeField(index, value);
   return Api::Success();
@@ -2172,7 +2141,7 @@
   if (isolate->top_exit_frame_info() == 0) {
     // There are no dart frames on the stack so it would be illegal to
     // throw an exception here.
-    return Api::Error("No Dart frames on stack, cannot throw exception");
+    return Api::NewError("No Dart frames on stack, cannot throw exception");
   }
   const Instance& excp = Instance::CheckedHandle(Api::UnwrapHandle(exception));
   // Unwind all the API scopes till the exit frame before throwing an
@@ -2181,7 +2150,7 @@
   ASSERT(state != NULL);
   state->UnwindScopes(isolate->top_exit_frame_info());
   Exceptions::Throw(excp);
-  return Api::Error("Exception was not thrown, internal error");
+  return Api::NewError("Exception was not thrown, internal error");
 }
 
 
@@ -2192,7 +2161,7 @@
   if (isolate->top_exit_frame_info() == 0) {
     // There are no dart frames on the stack so it would be illegal to
     // throw an exception here.
-    return Api::Error("No Dart frames on stack, cannot throw exception");
+    return Api::NewError("No Dart frames on stack, cannot throw exception");
   }
   DARTSCOPE(isolate);
   const Instance& excp = Instance::CheckedHandle(Api::UnwrapHandle(exception));
@@ -2203,7 +2172,7 @@
   ASSERT(state != NULL);
   state->UnwindScopes(isolate->top_exit_frame_info());
   Exceptions::ReThrow(excp, stk);
-  return Api::Error("Exception was not re thrown, internal error");
+  return Api::NewError("Exception was not re thrown, internal error");
 }
 
 
@@ -2289,8 +2258,8 @@
   Library& library = Library::Handle(isolate->object_store()->root_library());
   if (!library.IsNull()) {
     const String& library_url = String::Handle(library.url());
-    return Api::Error("%s: A script has already been loaded from '%s'.",
-                      CURRENT_FUNC, library_url.ToCString());
+    return Api::NewError("%s: A script has already been loaded from '%s'.",
+                         CURRENT_FUNC, library_url.ToCString());
   }
   isolate->set_library_tag_handler(handler);
   library = Library::New(url_str);
@@ -2312,25 +2281,25 @@
   DARTSCOPE(isolate);
   TIMERSCOPE(time_script_loading);
   if (buffer == NULL) {
-    return Api::Error("%s expects argument 'buffer' to be non-null.",
-                      CURRENT_FUNC);
+    return Api::NewError("%s expects argument 'buffer' to be non-null.",
+                         CURRENT_FUNC);
   }
   const Snapshot* snapshot = Snapshot::SetupFromBuffer(buffer);
   if (!snapshot->IsScriptSnapshot()) {
-    return Api::Error("%s expects parameter 'buffer' to be a script type"
-                      " snapshot", CURRENT_FUNC);
+    return Api::NewError("%s expects parameter 'buffer' to be a script type"
+                         " snapshot", CURRENT_FUNC);
   }
   Library& library = Library::Handle(isolate->object_store()->root_library());
   if (!library.IsNull()) {
     const String& library_url = String::Handle(library.url());
-    return Api::Error("%s: A script has already been loaded from '%s'.",
-                      CURRENT_FUNC, library_url.ToCString());
+    return Api::NewError("%s: A script has already been loaded from '%s'.",
+                         CURRENT_FUNC, library_url.ToCString());
   }
   SnapshotReader reader(snapshot, isolate);
   const Object& tmp = Object::Handle(reader.ReadObject());
   if (!tmp.IsLibrary()) {
-    return Api::Error("%s: Unable to deserialize snapshot correctly.",
-                      CURRENT_FUNC);
+    return Api::NewError("%s: Unable to deserialize snapshot correctly.",
+                         CURRENT_FUNC);
   }
   library ^= tmp.raw();
   library.Register();
@@ -2360,7 +2329,7 @@
   Dart_Handle result;
   const char* msg = CheckIsolateState(isolate);
   if (msg != NULL) {
-    return Api::Error(msg);
+    return Api::NewError(msg);
   }
   CompileAll(isolate, &result);
   return result;
@@ -2378,19 +2347,19 @@
   DARTSCOPE(Isolate::Current());
   const Object& param = Object::Handle(Api::UnwrapHandle(name));
   if (param.IsNull() || !param.IsString()) {
-    return Api::Error("Invalid class name specified");
+    return Api::NewError("Invalid class name specified");
   }
   const Library& lib = Library::CheckedHandle(Api::UnwrapHandle(library));
   if (lib.IsNull()) {
-    return Api::Error("Invalid parameter, Unknown library specified");
+    return Api::NewError("Invalid parameter, Unknown library specified");
   }
   String& cls_name = String::Handle();
   cls_name ^= param.raw();
   const Class& cls = Class::Handle(lib.LookupClass(cls_name));
   if (cls.IsNull()) {
     const String& lib_name = String::Handle(lib.name());
-    return Api::Error("Class '%s' not found in library '%s'.",
-                      cls_name.ToCString(), lib_name.ToCString());
+    return Api::NewError("Class '%s' not found in library '%s'.",
+                         cls_name.ToCString(), lib_name.ToCString());
   }
   return Api::NewLocalHandle(cls);
 }
@@ -2416,8 +2385,8 @@
   }
   const Library& library = Library::Handle(Library::LookupLibrary(url_str));
   if (library.IsNull()) {
-    return Api::Error("%s: library '%s' not found.",
-                      CURRENT_FUNC, url_str.ToCString());
+    return Api::NewError("%s: library '%s' not found.",
+                         CURRENT_FUNC, url_str.ToCString());
   } else {
     return Api::NewLocalHandle(library);
   }
@@ -2442,8 +2411,8 @@
   } else if (!library.LoadNotStarted()) {
     // The source for this library has either been loaded or is in the
     // process of loading.  Return an error.
-    return Api::Error("%s: library '%s' has already been loaded.",
-                      CURRENT_FUNC, url_str.ToCString());
+    return Api::NewError("%s: library '%s' has already been loaded.",
+                         CURRENT_FUNC, url_str.ToCString());
   }
   Dart_Handle result;
   CompileSource(isolate,