base: Remove non-caching discardable memory implementation.

base/memory/discardable_memory_malloc.cc

-// 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_malloc.h"
-
-#include "base/logging.h"
-
-namespace base {
-namespace internal {
-
-DiscardableMemoryMalloc::DiscardableMemoryMalloc(size_t size) : size_(size) {
-}
-
-DiscardableMemoryMalloc::~DiscardableMemoryMalloc() {
-}
-
-bool DiscardableMemoryMalloc::Initialize() {
-  return Lock() != DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
-}
-
-DiscardableMemoryLockStatus DiscardableMemoryMalloc::Lock() {
-  DCHECK(!memory_);
-
-  memory_.reset(static_cast<uint8*>(malloc(size_)));
-  if (!memory_)
-    return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
-
-  return DISCARDABLE_MEMORY_LOCK_STATUS_PURGED;
-}
-
-void DiscardableMemoryMalloc::Unlock() {
-  DCHECK(memory_);
-  memory_.reset();
-}
-
-void* DiscardableMemoryMalloc::Memory() const {
-  DCHECK(memory_);
-  return memory_.get();
-}
-
-}  // namespace internal
-}  // namespace base