Add permissions buts for Pepper plugins.

ppapi/shared_impl/ppapi_permissions.cc

+// Copyright (c) 2012 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/shared_impl/ppapi_permissions.h"
+
+#include "base/logging.h"
+
+namespace ppapi {
+
+PpapiPermissions::PpapiPermissions() : permissions_(0) {
+}
+
+PpapiPermissions::PpapiPermissions(uint32 perms) : permissions_(perms) {
+}
+
+PpapiPermissions::~PpapiPermissions() {
+}
+
+bool PpapiPermissions::HasPermission(Permission perm) const {
+  // Check that "perm" is a power of two to make sure the caller didn't set
+  // more than one permission bit. We may want to change how permissions are
+  // represented in the future so don't want callers making assumptions about
+  // bits.
+  uint32 perm_int = static_cast<uint32>(perm);
+  DCHECK((perm_int & (perm_int - 1)) == 0);
+  return !!(permissions_ & perm_int);
+}
+
+}  // namespace ppapi