[tracing] Add a memory dump provider for DOM storage

content/browser/dom_storage/session_storage_database.cc

 // 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.
 
 #include "content/browser/dom_storage/session_storage_database.h"
 
 #include <stddef.h>
 
 #include <vector>
 
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
 #include "third_party/leveldatabase/env_chromium.h"
 #include "third_party/leveldatabase/src/include/leveldb/db.h"
 #include "third_party/leveldatabase/src/include/leveldb/iterator.h"
 #include "third_party/leveldatabase/src/include/leveldb/options.h"
 #include "third_party/leveldatabase/src/include/leveldb/status.h"
 #include "third_party/leveldatabase/src/include/leveldb/write_batch.h"
 #include "url/gurl.h"
 
 
 namespace {
@@ skipping 291 matching lines @@
     } else {
       // The key is of the form "namespace-<namespaceid>-<origin>".
       std::string origin = key.substr(current_namespace_start_key.length());
       (*namespaces_and_origins)[current_namespace_id].push_back(GURL(origin));
     }
   }
   db_->ReleaseSnapshot(options.snapshot);
   return true;
 }
 
+bool SessionStorageDatabase::OnMemoryDump(
+    base::trace_event::ProcessMemoryDump* pmd) {
+  std::string db_memory_usage;
+  {
+    base::AutoLock lock(db_lock_);
+    // Return true if |db_| is null to prevent the dump provider from being
+    // disabled, since it can be created lazily.
+    if (!db_)
+      return true;
+
+    bool res =
+        db_->GetProperty("leveldb.approximate-memory-usage", &db_memory_usage);
+    DCHECK(res);
+  }
+
+  uint64_t size;
+  bool res = base::StringToUint64(db_memory_usage, &size);
+  DCHECK(res);
+
+  auto mad = pmd->CreateAllocatorDump(
+      base::StringPrintf("dom_storage/session_storage_%p", this));
+  mad->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                 base::trace_event::MemoryAllocatorDump::kUnitsBytes, size);
+
+  // Memory is allocated from system allocator (malloc).
+  const char* system_allocator_name =
+      base::trace_event::MemoryDumpManager::GetInstance()
+          ->system_allocator_pool_name();
+  if (system_allocator_name)
+    pmd->AddSuballocation(mad->guid(), system_allocator_name);
+  return true;
+}
 bool SessionStorageDatabase::LazyOpen(bool create_if_needed) {
   base::AutoLock auto_lock(db_lock_);
   if (db_error_ || is_inconsistent_) {
     // Don't try to open a database that we know has failed already.
     return false;
   }
   if (IsOpen())
     return true;
 
   if (!create_if_needed &&
@@ skipping 390 matching lines @@
 std::string SessionStorageDatabase::MapKey(const std::string& map_id,
                                            const std::string& key) {
   return base::StringPrintf("map-%s-%s", map_id.c_str(), key.c_str());
 }
 
 const char* SessionStorageDatabase::NextMapIdKey() {
   return "next-map-id";
 }
 
 }  // namespace content