Add support to create memory allocator dump in base::DiscardableMemory

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 76 matching lines @@
 
   // Dumps memory statistics for chrome://tracing.
   bool OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd);
 
   // Returns a unique identifier for a given tuple of (process id, segment id)
   // that can be used to match memory dumps across different processes.
   static base::trace_event::MemoryAllocatorDumpGuid GetSegmentGUIDForTracing(
       uint64 tracing_process_id,
       int32 segment_id);
 
+  // Returns a MemoryAllocatorDump for a given span on |pmd| with the size of
+  // the span.
+  base::trace_event::MemoryAllocatorDump* CreateMemoryAllocatorDump(
+      Span* span,
+      const char* name,
+      base::trace_event::ProcessMemoryDump* pmd) const;
+
  private:
   class ScopedMemorySegment {
    public:
     ScopedMemorySegment(DiscardableSharedMemoryHeap* heap,
                         scoped_ptr<base::DiscardableSharedMemory> shared_memory,
                         size_t size,
                         int32_t id,
                         const base::Closure& deleted_callback);
     ~ScopedMemorySegment();
 
     bool IsUsed() const;
     bool IsResident() const;
 
+    base::trace_event::MemoryAllocatorDump* CreateMemoryAllocatorDump(
+        Span* span,
+        const char* name,
+        base::trace_event::ProcessMemoryDump* pmd) const;
+
     // Used for dumping memory statistics from the segment to chrome://tracing.
     void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd) const;
 
    private:
     DiscardableSharedMemoryHeap* const heap_;
     scoped_ptr<base::DiscardableSharedMemory> shared_memory_;
     const size_t size_;
     const int32_t id_;
     const base::Closure deleted_callback_;
 
@@ skipping 33 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_