1 files changed, 35 insertions, 0 deletions
diff --git a/third_party/base/allocator/partition_allocator/partition_direct_map_extent.h b/third_party/base/allocator/partition_allocator/partition_direct_map_extent.h
new file mode 100644
index 0000000000..192c5b4b3d
--- /dev/null
+++ b/third_party/base/allocator/partition_allocator/partition_direct_map_extent.h
@@ -0,0 +1,35 @@
+// Copyright (c) 2018 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.
+
+#ifndef THIRD_PARTY_BASE_ALLOCATOR_PARTITION_ALLOCATOR_PARTITION_DIRECT_MAP_EXTENT_H_
+#define THIRD_PARTY_BASE_ALLOCATOR_PARTITION_ALLOCATOR_PARTITION_DIRECT_MAP_EXTENT_H_
+
+#include "third_party/base/allocator/partition_allocator/partition_bucket.h"
+#include "third_party/base/allocator/partition_allocator/partition_page.h"
+
+namespace pdfium {
+namespace base {
+namespace internal {
+
+struct PartitionDirectMapExtent {
+  PartitionDirectMapExtent* next_extent;
+  PartitionDirectMapExtent* prev_extent;
+  PartitionBucket* bucket;
+  size_t map_size;  // Mapped size, not including guard pages and meta-data.
+
+  ALWAYS_INLINE static PartitionDirectMapExtent* FromPage(PartitionPage* page);
+};
+
+ALWAYS_INLINE PartitionDirectMapExtent* PartitionDirectMapExtent::FromPage(
+    PartitionPage* page) {
+  DCHECK(page->bucket->is_direct_mapped());
+  return reinterpret_cast<PartitionDirectMapExtent*>(
+      reinterpret_cast<char*>(page) + 3 * kPageMetadataSize);
+}
+
+}  // namespace internal
+}  // namespace base
+}  // namespace pdfium
+
+#endif  // THIRD_PARTY_BASE_ALLOCATOR_PARTITION_ALLOCATOR_PARTITION_DIRECT_MAP_EXTENT_H_