[tracing] Add a memory dump provider for DOM storage

content/browser/dom_storage/dom_storage_context_impl.h

 // Copyright (c) 2012 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_BROWSER_DOM_STORAGE_DOM_STORAGE_CONTEXT_IMPL_H_
 #define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_CONTEXT_IMPL_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/atomic_sequence_num.h"
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/time/time.h"
+#include "base/trace_event/memory_dump_provider.h"
 #include "content/common/content_export.h"
 #include "url/gurl.h"
 
 namespace base {
 class FilePath;
 class NullableString16;
 class Time;
 }
 
 namespace storage {
@@ skipping 23 matching lines @@
 //   Sessions (per-tab) cause the creation and deletion of session Namespaces.
 //
 // Session Namespaces are cloned by initially making a shallow copy of
 // all contained Areas, the shallow copies refer to the same refcounted Map,
 // and does a deep copy-on-write if needed.
 //
 // Classes intended to be used by an embedder are DOMStorageContextImpl,
 // DOMStorageHost, and DOMStorageSession. The other classes are for
 // internal consumption.
 class CONTENT_EXPORT DOMStorageContextImpl
-    : public base::RefCountedThreadSafe<DOMStorageContextImpl> {
+    : public base::RefCountedThreadSafe<DOMStorageContextImpl>,
+      public base::trace_event::MemoryDumpProvider {
  public:
   // An interface for observing Local and Session Storage events on the
   // background thread.
   class EventObserver {
    public:
     // |old_value| may be null on initial insert.
     virtual void OnDOMStorageItemSet(
         const DOMStorageArea* area,
         const base::string16& key,
         const base::string16& new_value,
@@ skipping 91 matching lines @@
 
   // Starts backing sessionStorage on disk. This function must be called right
   // after DOMStorageContextImpl is created, before it's used.
   void SetSaveSessionStorageOnDisk();
 
   // Deletes all namespaces which don't have an associated DOMStorageNamespace
   // alive. This function is used for deleting possible leftover data after an
   // unclean exit.
   void StartScavengingUnusedSessionStorage();
 
+  // base::trace_event::MemoryDumpProvider implementation.
+  bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
+                    base::trace_event::ProcessMemoryDump* pmd) override;
+
  private:
   friend class DOMStorageContextImplTest;
   FRIEND_TEST_ALL_PREFIXES(DOMStorageContextImplTest, Basics);
   friend class base::RefCountedThreadSafe<DOMStorageContextImpl>;
   typedef std::map<int64_t, scoped_refptr<DOMStorageNamespace>>
       StorageNamespaceMap;
 
-  ~DOMStorageContextImpl();
+  ~DOMStorageContextImpl() override;
 
   void ClearSessionOnlyOrigins();
 
   // For scavenging unused sessionStorages.
   void FindUnusedNamespaces();
   void FindUnusedNamespacesInCommitSequence(
       const std::set<std::string>& namespace_ids_in_use,
       const std::set<std::string>& protected_persistent_session_ids);
   void DeleteNextUnusedNamespace();
   void DeleteNextUnusedNamespaceInCommitSequence();
@@ skipping 36 matching lines @@
   std::set<std::string> protected_persistent_session_ids_;
 
   // Mapping between persistent namespace IDs and namespace IDs for
   // sessionStorage.
   std::map<std::string, int64_t> persistent_namespace_id_to_namespace_id_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_CONTEXT_IMPL_H_