[tracing] Add separate dump provider for sql connection

sql/connection_memory_dump_provider.h

+// 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.
+
+#ifndef SQL_SQL_CONNECTION_MEMORY_DUMP_PROVIDER_H

[Primiano Tucci (use gerrit), 2016/01/11 19:27:42]

nit s/SQL_SQL_/SQL_/

[ssid, 2016/01/12 12:23:07]

Done.

+#define SQL_SQL_CONNECTION_MEMORY_DUMP_PROVIDER_H
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/synchronization/lock.h"
+#include "base/trace_event/memory_dump_provider.h"
+
+struct sqlite3;
+
+namespace sql {
+
+class ConnectionMemoryDumpProvider
+    : public base::trace_event::MemoryDumpProvider {
+ public:
+  ConnectionMemoryDumpProvider(sqlite3* db, const std::string& name);
+  ~ConnectionMemoryDumpProvider() override;
+
+  void reset_database() {

[Primiano Tucci (use gerrit), 2016/01/11 19:27:42]

non-trivial methods should be CamelCased and be defined in the .cc
considering that you are taking a lock here, you definitely don't want this to
be considered as "trivial" :)

[ssid, 2016/01/12 12:23:08]

Done.

+    base::AutoLock l(lock_);

[Primiano Tucci (use gerrit), 2016/01/11 19:27:42]

nit: s/l/lock/ typically I see this in the codebase in this way (16 vs 280
results)

[ssid, 2016/01/12 12:23:07]

Done.

+    db_ = nullptr;
+  }
+
+  // base::trace_event::MemoryDumpProvider implementation.
+  bool OnMemoryDump(
+      const base::trace_event::MemoryDumpArgs& args,
+      base::trace_event::ProcessMemoryDump* process_memory_dump) override;
+
+ private:
+  // Not owned by ConnectionMemoryDumpProvider. Weak reference to the database

[Primiano Tucci (use gerrit), 2016/01/11 19:27:42]

remove the "weak reference to ..." it's confusing as it sounds like weak
pointer, which is not.

I think that just sqlite3* db_;  // not owned is sufficient

[ssid, 2016/01/12 12:23:07]

Done.

+  // in connection.
+  sqlite3* db_;
+  base::Lock lock_;
+  std::string name_;

[Primiano Tucci (use gerrit), 2016/01/11 19:27:42]

maybe s/name_/connection_name_/ ?

[ssid, 2016/01/12 12:23:07]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(ConnectionMemoryDumpProvider);
+};
+
+}  // namespace sql
+
+#endif  // SQL_SQL_CONNECTION_MEMORY_DUMP_PROVIDER_H