Use DiscardableMemoryManager on Android.

base/memory/discardable_memory_ashmem.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/memory/discardable_memory_ashmem.h"
 
 #include "base/logging.h"
 
 namespace base {
 namespace internal {
 
-DiscardableMemoryMalloc::DiscardableMemoryMalloc(size_t size) : size_(size) {
+DiscardableMemoryAshmem::DiscardableMemoryAshmem(
+    DiscardableMemoryManager* manager,
+    size_t size)
+    : manager_(manager),
+      allocation_id_(manager->Register(size)),
+      memory_(NULL) {
 }
 
-DiscardableMemoryMalloc::~DiscardableMemoryMalloc() {
+DiscardableMemoryAshmem::~DiscardableMemoryAshmem() {
+  manager_->Unregister(allocation_id_);
 }
 
-bool DiscardableMemoryMalloc::Initialize() {
+bool DiscardableMemoryAshmem::Initialize() {
   return Lock() == DISCARDABLE_MEMORY_LOCK_STATUS_PURGED;
 }
 
-DiscardableMemoryLockStatus DiscardableMemoryMalloc::Lock() {
+DiscardableMemoryLockStatus DiscardableMemoryAshmem::Lock() {
   DCHECK(!memory_);
 
-  memory_.reset(static_cast<uint8*>(malloc(size_)));
+  bool purged = false;
+  memory_ = manager_->Lock(allocation_id_, &purged);
   if (!memory_)
     return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
 
-  return DISCARDABLE_MEMORY_LOCK_STATUS_PURGED;
+  return purged ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED
+                : DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS;
 }
 
-void DiscardableMemoryMalloc::Unlock() {
+void DiscardableMemoryAshmem::Unlock() {
   DCHECK(memory_);
-  memory_.reset();
+  manager_->Unlock(allocation_id_);
+  memory_ = NULL;
 }
 
-void* DiscardableMemoryMalloc::Memory() const {
+void* DiscardableMemoryAshmem::Memory() const {
   DCHECK(memory_);
-  return memory_.get();
+  return memory_;
 }
 
 }  // namespace internal
 }  // namespace base