HostDiscardableSharedMemoryManager should store the default memory limit

content/common/host_discardable_shared_memory_manager.h

 // 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 CONTENT_COMMON_HOST_DISCARDABLE_SHARED_MEMORY_MANAGER_H_
 #define CONTENT_COMMON_HOST_DISCARDABLE_SHARED_MEMORY_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 118 matching lines @@
 
   base::Lock lock_;
   typedef base::hash_map<DiscardableSharedMemoryId,
                          scoped_refptr<MemorySegment>> MemorySegmentMap;
   typedef base::hash_map<int, MemorySegmentMap> ProcessMap;
   ProcessMap processes_;
   // Note: The elements in |segments_| are arranged in such a way that they form
   // a heap. The LRU memory segment always first.
   typedef std::vector<scoped_refptr<MemorySegment>> MemorySegmentVector;
   MemorySegmentVector segments_;
+  size_t default_memory_limit_;
   size_t memory_limit_;
   size_t bytes_allocated_;
   std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
   scoped_refptr<base::SingleThreadTaskRunner>
       enforce_memory_policy_task_runner_;
   base::Closure enforce_memory_policy_callback_;
   bool enforce_memory_policy_pending_;
   base::WeakPtrFactory<HostDiscardableSharedMemoryManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HostDiscardableSharedMemoryManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_HOST_DISCARDABLE_SHARED_MEMORY_MANAGER_H_