Update from https://crrev.com/320931

base/test/test_discardable_memory_shmem_allocator.h

+// Copyright 2015 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 BASE_TEST_TEST_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_
+#define BASE_TEST_TEST_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_
+
+#include "base/memory/discardable_memory_shmem_allocator.h"
+
+namespace base {
+
+class TestDiscardableMemoryShmemAllocator
+    : public DiscardableMemoryShmemAllocator {
+ public:
+  TestDiscardableMemoryShmemAllocator();
+  ~TestDiscardableMemoryShmemAllocator() override;
+
+  // Overridden from DiscardableMemoryShmemAllocator:
+  scoped_ptr<DiscardableMemoryShmemChunk> AllocateLockedDiscardableMemory(
+      size_t size) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestDiscardableMemoryShmemAllocator);
+};
+
+}  // namespace base
+
+#endif  // BASE_TEST_TEST_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_