Reland r267170 "Use DiscardableMemoryManager on Android."

base/memory/discardable_memory_ashmem.h

-// Copyright 2013 The Chromium Authors. All rights reserved.
+// 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.
 
-#ifndef BASE_MEMORY_DISCARDABLE_MEMORY_EMULATED_H_
-#define BASE_MEMORY_DISCARDABLE_MEMORY_EMULATED_H_
+#ifndef BASE_MEMORY_DISCARDABLE_MEMORY_ASHMEM_H_
+#define BASE_MEMORY_DISCARDABLE_MEMORY_ASHMEM_H_
 
 #include "base/memory/discardable_memory.h"
 
+#include "base/macros.h"
 #include "base/memory/discardable_memory_manager.h"
 
 namespace base {
 namespace internal {
 
-class DiscardableMemoryEmulated
+class DiscardableAshmemChunk;
+class DiscardableMemoryAshmemAllocator;
+class DiscardableMemoryManager;
+
+class DiscardableMemoryAshmem
     : public DiscardableMemory,
       public internal::DiscardableMemoryManagerAllocation {
  public:
-  explicit DiscardableMemoryEmulated(size_t size);
-  virtual ~DiscardableMemoryEmulated();
+  explicit DiscardableMemoryAshmem(size_t bytes,
+                                   DiscardableMemoryAshmemAllocator* allocator,
+                                   DiscardableMemoryManager* manager);
 
-  static void RegisterMemoryPressureListeners();
-  static void UnregisterMemoryPressureListeners();
-
-  static void PurgeForTesting();
+  virtual ~DiscardableMemoryAshmem();
 
   bool Initialize();
 
   // Overridden from DiscardableMemory:
   virtual DiscardableMemoryLockStatus Lock() OVERRIDE;
   virtual void Unlock() OVERRIDE;
   virtual void* Memory() const OVERRIDE;
 
   // Overridden from internal::DiscardableMemoryManagerAllocation:
-  virtual bool AllocateAndAcquireLock(size_t bytes) OVERRIDE;
-  virtual void ReleaseLock() OVERRIDE {}
+  virtual bool AllocateAndAcquireLock() OVERRIDE;
+  virtual void ReleaseLock() OVERRIDE;
   virtual void Purge() OVERRIDE;
 
  private:
-  scoped_ptr<uint8[]> memory_;
+  const size_t bytes_;
+  DiscardableMemoryAshmemAllocator* const allocator_;
+  DiscardableMemoryManager* const manager_;
   bool is_locked_;
+  scoped_ptr<DiscardableAshmemChunk> ashmem_chunk_;
 
-  DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryEmulated);
+  DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryAshmem);
 };
 
 }  // namespace internal
 }  // namespace base
 
-#endif  // BASE_MEMORY_DISCARDABLE_MEMORY_EMULATED_H_
+#endif  // BASE_MEMORY_DISCARDABLE_MEMORY_ASHMEM_H_