Windows complains:

runtime/vm/raw_object.h

 // Copyright (c) 2012, 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.
 
 #ifndef VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/token.h"
@@ skipping 1253 matching lines @@
   RAW_HEAP_OBJECT_IMPLEMENTATION(Int8Array);
 
   // Variable length data follows here.
   int8_t data_[0];
 };
 
 
 class RawUint8Array : public RawByteArray {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Uint8Array);
 
- protected:
   // Variable length data follows here.
   uint8_t data_[0];
 };
 
 
-class RawUint8ClampedArray : public RawUint8Array {
+class RawUint8ClampedArray : public RawByteArray {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Uint8ClampedArray);
+
+  // Variable length data follows here.
+  uint8_t data_[0];
 };
 
 
 class RawInt16Array : public RawByteArray {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Int16Array);
 
   // Variable length data follows here.
   int16_t data_[0];
 };
 
@@ skipping 362 matching lines @@
          kExternalUint64ArrayCid == kExternalInt8ArrayCid + 8 &&
          kExternalFloat32ArrayCid == kExternalInt8ArrayCid + 9 &&
          kExternalFloat64ArrayCid == kExternalInt8ArrayCid + 10 &&
          kStacktraceCid == kExternalInt8ArrayCid + 11);
   return (index >= kExternalInt8ArrayCid && index <= kExternalFloat64ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_