Canvas.concat takes a 16-element Float32List instead of an array.

sky/engine/tonic/dart_float32list.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sky/engine/config.h"
+#include "sky/engine/tonic/dart_error.h"
+#include "sky/engine/tonic/dart_float32list.h"
+
+namespace blink {
+
+Float32List::Float32List(Dart_Handle list)
+    : data_(nullptr), num_elements_(0), dart_handle_(list) {
+  if (Dart_IsNull(list))
+    return;
+
+  Dart_TypedData_Type type;
+  Dart_TypedDataAcquireData(
+      list, &type, reinterpret_cast<void**>(&data_), &num_elements_);
+  DCHECK(!LogIfError(list));
+  ASSERT(type == Dart_TypedData_kFloat32);
+}
+
+Float32List::Float32List(Float32List&& other)
+    : data_(other.data_),
+      num_elements_(other.num_elements_),
+      dart_handle_(other.dart_handle_) {
+  other.data_ = nullptr;

[abarth-chromium, 2015/06/04 17:29:28]

I'd null out the other dart_handle_ too for paranoia.

[Matt Perry, 2015/06/04 17:34:35]

Done.

+}
+
+Float32List::~Float32List() {
+  if (data_)
+    Dart_TypedDataReleaseData(dart_handle_);
+}
+
+Float32List DartConverter<Float32List>::FromArgumentsWithNullCheck(
+    Dart_NativeArguments args,
+    int index,
+    Dart_Handle& exception) {
+  Dart_Handle list = Dart_GetNativeArgument(args, index);
+  DCHECK(!LogIfError(list));
+
+  Float32List result(list);
+  return std::move(result);

[abarth-chromium, 2015/06/04 17:29:28]

return Float32List(list);

No need for std::move.

[Matt Perry, 2015/06/04 17:34:35]

Done.

+}
+
+} // namespace blink