Add Dart class for _ExternalUint8ClampedArray and API to allocate it.

runtime/vm/dart_api_impl.cc

 // 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.
 
 #include "include/dart_api.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
@@ skipping 2222 matching lines @@
   DARTSCOPE(isolate);
   if (data == NULL && length != 0) {
     RETURN_NULL_ERROR(data);
   }
   CHECK_LENGTH(length, ExternalUint8Array::kMaxElements);
   return Api::NewHandle(
       isolate, ExternalUint8Array::New(data, length, peer, callback));
 }
 
 
+DART_EXPORT Dart_Handle Dart_NewExternalClampedByteArray(
+    uint8_t* data,
+    intptr_t length,
+    void* peer,
+    Dart_PeerFinalizer callback) {
+  Isolate* isolate = Isolate::Current();
+  DARTSCOPE(isolate);
+  if (data == NULL && length != 0) {
+    RETURN_NULL_ERROR(data);
+  }
+  CHECK_LENGTH(length, ExternalUint8ClampedArray::kMaxElements);
+  return Api::NewHandle(
+      isolate, ExternalUint8ClampedArray::New(data, length, peer, callback));
+}
+
+
 DART_EXPORT Dart_Handle Dart_ExternalByteArrayGetData(Dart_Handle object,
                                                       void** data) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   const ExternalUint8Array& array =
       Api::UnwrapExternalUint8ArrayHandle(isolate, object);
   if (array.IsNull()) {
     RETURN_TYPE_ERROR(isolate, object, ExternalUint8Array);
   }
   if (data == NULL) {
@@ skipping 2250 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success(isolate);
 }
 
 }  // namespace dart