base: Refactor DiscardableMemoryManager for use with different type of allocations.

base/memory/discardable_memory_emulated.cc

 // Copyright 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_emulated.h"
 
 #include "base/lazy_instance.h"
 #include "base/memory/discardable_memory_manager.h"
 
 namespace base {
-
 namespace {
 
 base::LazyInstance<internal::DiscardableMemoryManager>::Leaky g_manager =
     LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 namespace internal {
 
 DiscardableMemoryEmulated::DiscardableMemoryEmulated(size_t size)
@@ skipping 23 matching lines @@
 }
 
 bool DiscardableMemoryEmulated::Initialize() {
   return Lock() == DISCARDABLE_MEMORY_LOCK_STATUS_PURGED;
 }
 
 DiscardableMemoryLockStatus DiscardableMemoryEmulated::Lock() {
   DCHECK(!is_locked_);
 
   bool purged = false;
-  memory_ = g_manager.Pointer()->Acquire(this, &purged);
-  if (!memory_)
+  if (!g_manager.Pointer()->AcquireLock(this, &purged))
     return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
 
   is_locked_ = true;
   return purged ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED
                 : DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS;
 }
 
 void DiscardableMemoryEmulated::Unlock() {
   DCHECK(is_locked_);
-  g_manager.Pointer()->Release(this, memory_.Pass());
+  g_manager.Pointer()->ReleaseLock(this);
   is_locked_ = false;
 }
 
 void* DiscardableMemoryEmulated::Memory() const {
+  DCHECK(is_locked_);
   DCHECK(memory_);
   return memory_.get();
 }
 
+bool DiscardableMemoryEmulated::AllocateAndAcquireLock(size_t bytes) {
+  if (memory_)
+    return true;
+
+  memory_.reset(new uint8[bytes]);
+  return false;
+}
+
+void DiscardableMemoryEmulated::Purge() {
+  memory_.reset();
+}
+
 }  // namespace internal
 }  // namespace base