[tracing] Add a memory dump provider for DOM storage

content/browser/dom_storage/dom_storage_area.h

 // Copyright 2013 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_AREA_H_
 #define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_AREA_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/nullable_string16.h"
 #include "base/strings/string16.h"
 #include "content/common/content_export.h"
 #include "content/common/dom_storage/dom_storage_types.h"
 #include "url/gurl.h"
 
+namespace base {
+namespace trace_event {
+class ProcessMemoryDump;
+}
+}
+
 namespace content {
 
 class DOMStorageDatabaseAdapter;
 class DOMStorageMap;
 class DOMStorageTaskRunner;
 class SessionStorageDatabase;
 
 // Container for a per-origin Map of key/value pairs potentially
 // backed by storage on disk and lazily commits changes to disk.
 // See class comments for DOMStorageContextImpl for a larger overview.
@@ skipping 55 matching lines @@
   void PurgeMemory();
 
   // Schedules the commit of any unsaved changes and enters a
   // shutdown state such that the value getters and setters will
   // no longer do anything.
   void Shutdown();
 
   // Returns true if the data is loaded in memory.
   bool IsLoadedInMemory() const { return is_initial_import_done_; }
 
+  // Adds memory statistics to |pmd| for chrome://tracing.
+  void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd);
+
  private:
   friend class DOMStorageAreaTest;
   FRIEND_TEST_ALL_PREFIXES(DOMStorageAreaTest, DOMStorageAreaBasics);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageAreaTest, BackingDatabaseOpened);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageAreaTest, TestDatabaseFilePath);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageAreaTest, CommitTasks);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageAreaTest, CommitChangesAtShutdown);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageAreaTest, DeleteOrigin);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageAreaTest, PurgeMemory);
   FRIEND_TEST_ALL_PREFIXES(DOMStorageAreaTest, RateLimiter);
@@ skipping 71 matching lines @@
   base::TimeTicks start_time_;
   RateLimiter data_rate_limiter_;
   RateLimiter commit_rate_limiter_;
 
   DISALLOW_COPY_AND_ASSIGN(DOMStorageArea);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_AREA_H_