[tracing] Add sqlite memory statistics to tracing.

sql/sql_memory_dump_provider.h

Index: sql/sql_memory_dump_provider.h
diff --git a/sql/sql_memory_dump_provider.h b/sql/sql_memory_dump_provider.h
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+// 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_PROCESS_MEMORY_DUMP_PROVIDER_H
+#define SQL_PROCESS_MEMORY_DUMP_PROVIDER_H
+
+#include "base/memory/singleton.h"
+#include "base/trace_event/memory_dump_provider.h"
+#include "sql/sql_export.h"
+
+namespace sql {
+
+// Adds process-wide memory usage statistics about sqlite to chrome://tracing.
+// sql::Connection::OnMemoryDump adds per-connection memory statistics.
+class SQL_EXPORT SqlMemoryDumpProvider
+    : public base::trace_event::MemoryDumpProvider {
+ public:
+  static SqlMemoryDumpProvider* GetInstance();
+
+  // MemoryDumpProvider implementation.
+  bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
+                    base::trace_event::ProcessMemoryDump* pmd) override;
+
+ private:
+  friend struct base::DefaultSingletonTraits<SqlMemoryDumpProvider>;
+
+  SqlMemoryDumpProvider();
+  ~SqlMemoryDumpProvider() override;
+
+  DISALLOW_COPY_AND_ASSIGN(SqlMemoryDumpProvider);
+};
+
+}  // namespace sql
+
+#endif  // SQL_PROCESS_MEMORY_DUMP_PROVIDER_H