Add guards to metric values; erase bad events/metrics from db

chrome/browser/performance_monitor/constants.cc

 // Copyright (c) 2012 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 "chrome/browser/performance_monitor/constants.h"
 
+#include "base/time.h"
+
 namespace performance_monitor {
 
-// TODO(chebert): i18n on all constants.
-
 // The error message displayed when a metric's details are not found.
 const char kMetricNotFoundError[] = "Metric details not found.";
 
 // Any metric that is not associated with a specific activity will use this as
 // its activity.
 const char kProcessChromeAggregate[] = "chrome_aggregate";
 
 // The default interval at which PerformanceMonitor performs its timed
 // collections; this can be overridden by using the kPerformanceMonitorGathering
 // switch with an associated (positive integer) value.
 const int kDefaultGatherIntervalInSeconds = 120;
 
 // Tokens to retrieve state values from the database.
 
 // Stores information about the previous chrome version.
 const char kStateChromeVersion[] = "chrome_version";
 // The prefix to the state of a profile's name, to prevent any possible naming
 // collisions in the database.
 const char kStateProfilePrefix[] = "profile";
 
+// Unit values
+// Memory measurements
+const int64 kBytesPerKilobyte = 1 << 10;
+const int64 kBytesPerMegabyte = kBytesPerKilobyte * (1 << 10);
+const int64 kBytesPerGigabyte = kBytesPerMegabyte * (1 << 10);
+const int64 kBytesPerTerabyte = kBytesPerGigabyte * (1 << 10);
+
+// Time measurements
+const int64 kMicrosecondsPerMonth = base::Time::kMicrosecondsPerDay * 30;
+const int64 kMicrosecondsPerYear = base::Time::kMicrosecondsPerDay * 365;
+
+
 }  // namespace performance_monitor