base: Rename discardable memory allocator interface and remove unnecessary class.

base/memory/discardable_memory_shmem_allocator.cc

Index: base/memory/discardable_memory_shmem_allocator.cc
diff --git a/base/memory/discardable_memory_shmem_allocator.cc b/base/memory/discardable_memory_shmem_allocator.cc
deleted file mode 100644
index a87c58d415d480d2cac8b7dc30389222d78e557f..0000000000000000000000000000000000000000
--- a/base/memory/discardable_memory_shmem_allocator.cc
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright 2014 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 "base/memory/discardable_memory_shmem_allocator.h"
-
-#include "base/lazy_instance.h"
-#include "base/logging.h"
-#include "base/memory/discardable_shared_memory.h"
-
-namespace base {
-namespace {
-
-DiscardableMemoryShmemAllocator* g_allocator = nullptr;
-
-}  // namespace
-
-// static
-void DiscardableMemoryShmemAllocator::SetInstance(
-    DiscardableMemoryShmemAllocator* allocator) {
-  DCHECK(allocator);
-
-  // Make sure this function is only called once before the first call
-  // to GetInstance().
-  DCHECK(!g_allocator);
-
-  g_allocator = allocator;
-}
-
-// static
-DiscardableMemoryShmemAllocator*
-DiscardableMemoryShmemAllocator::GetInstance() {
-  DCHECK(g_allocator);
-  return g_allocator;
-}
-
-}  // namespace base