Make auto-roller roll recent release based on timestamp.

tools/release/releases.py

 #!/usr/bin/env python
 # Copyright 2014 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This script retrieves the history of all V8 branches and
 # their corresponding Chromium revisions.
 
 # Requires a chromium checkout with branch heads:
 # gclient sync --with_branch_heads
@@ skipping 276 matching lines @@
     # Clean up checked-out version file.
     self.GitCheckoutFileSafe(VERSION_FILE, "HEAD")
     return releases
 
 
   def RunStep(self):
     self.GitCreateBranch(self._config["BRANCHNAME"])
     releases = []
     if self._options.branch == 'recent':
       # List every release from the last 7 days.
-      revisions = self.GetRecentReleases(max_age=7 * 24 * 60 * 60)
+      revisions = self.GetRecentReleases(max_age=7 * DAY_IN_SECONDS)
       for revision in revisions:
         releases += self.GetReleaseFromRevision(revision)
     elif self._options.branch == 'all':  # pragma: no cover
       # Retrieve the full release history.
       for branch in self.vc.GetBranches():
         releases += self.GetReleasesFromBranch(branch)
       releases += self.GetReleasesFromBranch(self.vc.CandidateBranch())
       releases += self.GetReleasesFromBranch(self.vc.MasterBranch())
     else:  # pragma: no cover
       # Retrieve history for a specified branch.
@@ skipping 196 matching lines @@
       UpdateChromiumCheckout,
       RetrieveChromiumV8Releases,
       RietrieveChromiumBranches,
       CleanUp,
       WriteOutput,
     ]
 
 
 if __name__ == "__main__":  # pragma: no cover
   sys.exit(Releases().Run())