Keep all references to kInstallDate inside components/metrics/

chrome/browser/chrome_browser_field_trials_desktop.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 CHROME_BROWSER_CHROME_BROWSER_FIELD_TRIALS_DESKTOP_H_
 #define CHROME_BROWSER_CHROME_BROWSER_FIELD_TRIALS_DESKTOP_H_
 
 #include "base/basictypes.h"
 #include "base/time/time.h"
 
 class PrefService;
 
 namespace base {
 class CommandLine;
 }
 
 namespace chrome {
 
 // Sets up common desktop-only field trials.
 // Add an invocation of your field trial init function to this method, or to
 // SetupFieldTrials in chrome_browser_field_trials.cc if it is for all
 // platforms.
 // |local_state| is needed by some other methods called from within this one.
 void SetupDesktopFieldTrials(const base::CommandLine& parsed_command_line,
-                             const base::Time& install_time,
                              PrefService* local_state);
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_CHROME_BROWSER_FIELD_TRIALS_DESKTOP_H_