Refactor DiscardableMemory for the upcoming DiscardableMemoryAllocator.

base/memory/discardable_memory.cc

 // Copyright (c) 2013 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.h"
 
+#include "base/compiler_specific.h"
 #include "base/logging.h"
 
 namespace base {
 
-DiscardableMemory::DiscardableMemory()
-    : memory_(NULL),
-      size_(0),
-      is_locked_(false)
-#if defined(OS_ANDROID)
-      , fd_(-1)
-#endif  // OS_ANDROID
-      {
-  DCHECK(Supported());
-}
-
-void* DiscardableMemory::Memory() const {
-  DCHECK(is_locked_);
-  return memory_;
-}
-
 // Stub implementations for platforms that don't support discardable memory.
 
 #if !defined(OS_ANDROID) && !defined(OS_MACOSX)
 
-DiscardableMemory::~DiscardableMemory() {
-  NOTIMPLEMENTED();
-}
-
 // static
 bool DiscardableMemory::Supported() {
   return false;
 }
 
-bool DiscardableMemory::InitializeAndLock(size_t size) {
-  NOTIMPLEMENTED();
-  return false;
-}
-
-LockDiscardableMemoryStatus DiscardableMemory::Lock() {
-  NOTIMPLEMENTED();
-  return DISCARDABLE_MEMORY_FAILED;
-}
-
-void DiscardableMemory::Unlock() {
-  NOTIMPLEMENTED();
+// static
+scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemory(
+    size_t size) {
+  return scoped_ptr<DiscardableMemory>();
 }
 
 // static
 bool DiscardableMemory::PurgeForTestingSupported() {
   return false;
 }
 
 // static
 void DiscardableMemory::PurgeForTesting() {
   NOTIMPLEMENTED();
 }
 
 #endif  // OS_*
 
 }  // namespace base