Add DiscardableMemoryAllocator to work around FD limit issue.

base/memory/discardable_memory_android.h

+// 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.
+
+// Please use discardable_memory.h since this is just an internal file providing
+// utility functions used both by discardable_memory_android.cc and
+// discardable_memory_allocator_android.cc.
+
+#ifndef BASE_MEMORY_DISCARDABLE_MEMORY_ANDROID_H_
+#define BASE_MEMORY_DISCARDABLE_MEMORY_ANDROID_H_
+
+#include "base/basictypes.h"
+#include "base/memory/discardable_memory.h"
+
+namespace base {
+namespace internal {
+
+size_t AlignToNextPage(size_t size);
+
+bool CreateAshmemRegion(const char* name, size_t size, int* fd, void** address);
+
+bool CloseAshmemRegion(int fd, size_t size, void* address);
+
+LockDiscardableMemoryStatus LockAshmemRegion(int fd,
+                                             size_t offset,
+                                             size_t size,
+                                             const void* address);
+
+bool UnlockAshmemRegion(int fd,
+                        size_t offset,
+                        size_t size,
+                        const void* address);
+
+}  // namespace internal
+}  // namespace base
+
+#endif  // BASE_MEMORY_DISCARDABLE_MEMORY_ANDROID_H_