Allow String.fromCharCodes to work directly on a GrowableObjectArray.

runtime/lib/string.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/bootstrap_natives.h"
 
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/symbols.h"
 #include "vm/unicode.h"
 
 namespace dart {
 
 DEFINE_NATIVE_ENTRY(StringBase_createFromCodePoints, 1) {
-  GET_NON_NULL_NATIVE_ARGUMENT(Array, a, arguments->NativeArgAt(0));
+  GET_NON_NULL_NATIVE_ARGUMENT(Instance, list, arguments->NativeArgAt(0));
+  if (!list.IsGrowableObjectArray() && !list.IsArray()) {
+    const Array& args = Array::Handle(Array::New(1));
+    args.SetAt(0, list);
+    Exceptions::ThrowByType(Exceptions::kArgument, args);
+  }
   // TODO(srdjan): Check that parameterized type is an int.
+
+  Array& a = Array::Handle();
+  intptr_t array_len;
+  if (list.IsGrowableObjectArray()) {
+    const GrowableObjectArray& growableArray = GrowableObjectArray::Cast(list);
+    a ^= growableArray.data();
+    array_len = growableArray.Length();
+  } else {
+    a ^= Array::Cast(list).raw();
+    array_len = a.Length();
+  }
+
   Zone* zone = isolate->current_zone();
-  intptr_t array_len = a.Length();
 
   // Unbox the array and determine the maximum element width.
   bool is_one_byte_string = true;
   intptr_t utf16_len = array_len;
   int32_t* utf32_array = zone->Alloc<int32_t>(array_len);
   Object& index_object = Object::Handle(isolate);
   for (intptr_t i = 0; i < array_len; i++) {
     index_object = a.At(i);
     if (!index_object.IsSmi()) {
       const Array& args = Array::Handle(Array::New(1));
@@ skipping 184 matching lines @@
       ? String::Handle(OneByteString::New(length_value, Heap::kNew))
       : String::Handle(TwoByteString::New(length_value, Heap::kNew));
   NoGCScope no_gc;
 
   uint16_t* data_position = reinterpret_cast<uint16_t*>(codeUnits.ByteAddr(0));
   String::Copy(result, 0, data_position, length_value);
   return result.raw();
 }
 
 }  // namespace dart