Pepper and WebKit API change to support a plugin knowing if a scrollbar is an overlay one.

ppapi/cpp/dev/scrollbar_group_dev.cc

+// Copyright (c) 2011 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 "ppapi/cpp/dev/scrollbar_group_dev.h"
+
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/module_impl.h"
+
+namespace pp {
+
+namespace {
+
+template <> const char* interface_name<PPB_ScrollbarGroup_Dev>() {
+  return PPB_SCROLLBAR_GROUP_DEV_INTERFACE;
+}
+
+}  // namespace
+
+ScrollbarGroup_Dev::ScrollbarGroup_Dev(PP_Resource resource)
+    : Resource(resource) {
+}
+
+ScrollbarGroup_Dev::ScrollbarGroup_Dev(const Instance& instance) {
+  if (!has_interface<PPB_ScrollbarGroup_Dev>())
+    return;
+  PassRefFromConstructor(get_interface<PPB_ScrollbarGroup_Dev>()->Create(
+      instance.pp_instance()));
+}
+
+ScrollbarGroup_Dev::ScrollbarGroup_Dev(const ScrollbarGroup_Dev& other)
+    : Resource(other) {
+}
+
+}  // namespace pp