Add a field trial for using lower sqlite cache sizes.

chrome/browser/history/history_field_trial.h

+// Copyright (c) 2011 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 CHROME_BROWSER_HISTORY_HISTORY_FIELD_TRIAL_H_
+#define CHROME_BROWSER_HISTORY_HISTORY_FIELD_TRIAL_H_
+

[Scott Hess - ex-Googler, 2011/10/28 23:18:19]

#pragma once
???

+#include <string>
+
+namespace history {
+
+class HistoryFieldTrial {
+ public:
+  static void Activate();
+
+  // Returns true if history should try to use less memory.
+  static bool IsLowMemFieldTrial();
+
+  // Returns the group name as a suffix to append to histogram names for the
+  // current field trial, or the empty string if none.
+  static std::string GetGroupSuffix();
+};
+
+}  // namespace history
+
+#endif  // CHROME_BROWSER_HISTORY_HISTORY_FIELD_TRIAL_H_