Reland of [tracing] Display the locked size of discardable memory segment.

content/common/discardable_shared_memory_heap.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_DISCARDABLE_SHARED_MEMORY_HEAP_H_
 #define CONTENT_COMMON_DISCARDABLE_SHARED_MEMORY_HEAP_H_
 
 #include "base/callback.h"
 #include "base/containers/hash_tables.h"
 #include "base/containers/linked_list.h"
@@ skipping 12 matching lines @@
 // is used to keep track of free blocks.
 class CONTENT_EXPORT DiscardableSharedMemoryHeap {
  public:
   class CONTENT_EXPORT Span : public base::LinkNode<Span> {
    public:
     ~Span();
 
     base::DiscardableSharedMemory* shared_memory() { return shared_memory_; }
     size_t start() const { return start_; }
     size_t length() const { return length_; }
+    void set_is_locked(bool is_locked) { is_locked_ = is_locked; }
 
    private:
     friend class DiscardableSharedMemoryHeap;
 
     Span(base::DiscardableSharedMemory* shared_memory,
          size_t start,
          size_t length);
 
     base::DiscardableSharedMemory* shared_memory_;
     size_t start_;
     size_t length_;
+    bool is_locked_;
 
     DISALLOW_COPY_AND_ASSIGN(Span);
   };
 
   explicit DiscardableSharedMemoryHeap(size_t block_size);
   ~DiscardableSharedMemoryHeap();
 
   // Grow heap using |shared_memory| and return a span for this new memory.
   // |shared_memory| must be aligned to the block size and |size| must be a
   // multiple of the block size. |deleted_callback| is called when
@@ skipping 114 matching lines @@
   // is a free list of runs that consist of k blocks. The 256th entry is a
   // free list of runs that have length >= 256 blocks.
   base::LinkedList<Span> free_spans_[256];
 
   DISALLOW_COPY_AND_ASSIGN(DiscardableSharedMemoryHeap);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_DISCARDABLE_SHARED_MEMORY_HEAP_H_