Improve the error message in BuildTime.InThePast to help figure out the problem.

base/build_time.cc

 // 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.
 
 #include "base/build_time.h"
 
 // Imports the generated build date, i.e. BUILD_DATE.
 #include "base/generated_build_date.h"
 
 #include "base/logging.h"
 #include "base/time/time.h"
 
 namespace base {
 
 Time GetBuildTime() {
   Time integral_build_time;
-  // BUILD_DATE is exactly "Mmm DD YYYY".
-  const char kDateTime[] = BUILD_DATE " 05:00:00";
-  bool result = Time::FromUTCString(kDateTime, &integral_build_time);
+  // BUILD_DATE is exactly "Mmm DD YYYY HH:MM:SS".
+  // See //build/write_build_date_header.py. "HH:MM:SS" is normally expected to
+  // be "05:00:00" but is not enforced here.
+  bool result = Time::FromUTCString(BUILD_DATE, &integral_build_time);
   DCHECK(result);
   return integral_build_time;
 }
 
 }  // namespace base