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

components/html_viewer/discardable_memory_allocator.cc

 // Copyright 2015 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.
 
 #include "components/html_viewer/discardable_memory_allocator.h"
 
 #include "base/memory/discardable_memory.h"
 #include "base/stl_util.h"
+#include "base/trace_event/memory_allocator_dump.h"
+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
 
 namespace html_viewer {
 
 // Interface to the rest of the program. These objects are owned outside of the
 // allocator.
 class DiscardableMemoryAllocator::DiscardableMemoryChunkImpl
     : public base::DiscardableMemory {
  public:
   DiscardableMemoryChunkImpl(size_t size, DiscardableMemoryAllocator* allocator)
       : is_locked_(true),
@@ skipping 27 matching lines @@
   }
 
   void* data() const override {
     if (data_) {
       DCHECK(is_locked_);
       return data_.get();
     }
     return nullptr;
   }
 
+  base::trace_event::MemoryAllocatorDump* CreateMemoryAllocatorDump(
+      const char* name,
+      base::trace_event::ProcessMemoryDump* pmd) const override {
+    base::trace_event::MemoryAllocatorDump* dump =
+        pmd->CreateAllocatorDump(name);
+    dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                    base::trace_event::MemoryAllocatorDump::kUnitsBytes, size_);
+
+    // Memory is allocated from system allocator (malloc).
+    pmd->AddSuballocation(dump->guid(),
+                          base::trace_event::MemoryDumpManager::GetInstance()
+                              ->system_allocator_pool_name());
+    return dump;
+  }
+
   size_t size() const { return size_; }
 
   void Discard() {
     DCHECK(!is_locked_);
     data_.reset();
   }
 
  private:
   bool is_locked_;
   size_t size_;
@@ skipping 53 matching lines @@
   live_unlocked_chunks_.erase(it);
 }
 
 void DiscardableMemoryAllocator::NotifyDestructed(
     std::list<DiscardableMemoryChunkImpl*>::iterator it) {
   base::AutoLock lock(lock_);
   live_unlocked_chunks_.erase(it);
 }
 
 }  // namespace html_viewer