Use buildtime to ensure stability stats

r=huanr
Review URL: http://codereview.chromium.org/548058

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@36549 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 32 insertions, 12 deletions

diff --git a/chrome/browser/metrics/metrics_log.cc b/chrome/browser/metrics/metrics_log.cc
index 4786923..4ce5273 100644
--- a/chrome/browser/metrics/metrics_log.cc
+++ b/chrome/browser/metrics/metrics_log.cc
@@ -38,8 +38,6 @@ inline const unsigned char* UnsignedChar(const char* input) {
   return reinterpret_cast<const unsigned char*>(input);
 }
 
-static int64 GetBuildTime();
-
 // static
 void MetricsLog::RegisterPrefs(PrefService* local_state) {
   local_state->RegisterListPref(prefs::kStabilityPluginStats);
@@ -316,6 +314,19 @@ std::string MetricsLog::GetVersionString() {
   return std::string();
 }
 
+// static
+int64 MetricsLog::GetBuildTime() {
+  static int64 integral_build_time = 0;
+  if (!integral_build_time) {
+    Time time;
+    const char* kDateTime = __DATE__ " " __TIME__ " GMT";
+    bool result = Time::FromString(ASCIIToWide(kDateTime).c_str(), &time);
+    DCHECK(result);
+    integral_build_time = static_cast<int64>(time.ToTimeT());
+  }
+  return integral_build_time;
+}
+
 std::string MetricsLog::GetInstallDate() const {
   PrefService* pref = g_browser_process->local_state();
   if (pref) {
@@ -713,11 +724,3 @@ void MetricsLog::RecordHistogramDelta(const Histogram& histogram,
     }
   }
 }
-
-static int64 GetBuildTime() {
-  Time parsed_time;
-  const char* kDateTime = __DATE__ " " __TIME__ " GMT";
-  bool result = Time::FromString(ASCIIToWide(kDateTime).c_str(), &parsed_time);
-  DCHECK(result);
-  return static_cast<int64>(parsed_time.ToTimeT());
-}
diff --git a/chrome/browser/metrics/metrics_log.h b/chrome/browser/metrics/metrics_log.h
index c8e7691..c1d5ff2 100644
--- a/chrome/browser/metrics/metrics_log.h
+++ b/chrome/browser/metrics/metrics_log.h
@@ -106,6 +106,12 @@ class MetricsLog {
   // Get the current version of the application as a string.
   static std::string GetVersionString();
 
+  // Get the GMT buildtime for the current binary, expressed in seconds since
+  // Januray 1, 1970 GMT.
+  // The value is used to identify when a new build is run, so that previous
+  // reliability stats, from other builds, can be abandoned.
+  static int64 GetBuildTime();
+
   // Use |extension| in all uploaded appversions in addition to the standard
   // version string.
   static void set_version_extension(const std::string& extension) {
diff --git a/chrome/browser/metrics/metrics_service.cc b/chrome/browser/metrics/metrics_service.cc
index 610792c..54cc138 100644
--- a/chrome/browser/metrics/metrics_service.cc
+++ b/chrome/browser/metrics/metrics_service.cc
@@ -322,6 +322,7 @@ void MetricsService::RegisterPrefs(PrefService* local_state) {
   local_state->RegisterInt64Pref(prefs::kStabilityLastTimestampSec, 0);
   local_state->RegisterInt64Pref(prefs::kStabilityUptimeSec, 0);
   local_state->RegisterStringPref(prefs::kStabilityStatsVersion, L"");
+  local_state->RegisterInt64Pref(prefs::kStabilityStatsBuildTime, 0);
   local_state->RegisterBooleanPref(prefs::kStabilityExitedCleanly, true);
   local_state->RegisterBooleanPref(prefs::kStabilitySessionEndCompleted, true);
   local_state->RegisterIntegerPref(prefs::kMetricsSessionID, -1);
@@ -664,13 +665,17 @@ void MetricsService::InitializeMetricsState() {
   PrefService* pref = g_browser_process->local_state();
   DCHECK(pref);
 
-  if (WideToUTF8(pref->GetString(prefs::kStabilityStatsVersion)) !=
-      MetricsLog::GetVersionString()) {
+  if ((pref->GetInt64(prefs::kStabilityStatsBuildTime)
+       != MetricsLog::GetBuildTime()) ||
+      (WideToUTF8(pref->GetString(prefs::kStabilityStatsVersion))
+       != MetricsLog::GetVersionString())) {
     // This is a new version, so we don't want to confuse the stats about the
     // old version with info that we upload.
     DiscardOldStabilityStats(pref);
     pref->SetString(prefs::kStabilityStatsVersion,
                     UTF8ToWide(MetricsLog::GetVersionString()));
+    pref->SetInt64(prefs::kStabilityStatsBuildTime,
+                   MetricsLog::GetBuildTime());
   }
 
   // Update session ID
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 31228ba..84f9267 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -353,6 +353,11 @@ const wchar_t kStabilityExitedCleanly[] =
 const wchar_t kStabilityStatsVersion[] =
     L"user_experience_metrics.stability.stats_version";
 
+// Build time, in seconds since an epoch, which is used to assure that stability
+// metrics reported reflect stability of the same build.
+extern const wchar_t kStabilityStatsBuildTime[] =
+    L"user_experience_metrics.stability.stats_buildtime";
+
 // False if we received a session end and either we crashed during processing
 // the session end or ran out of time and windows terminated us.
 const wchar_t kStabilitySessionEndCompleted[] =
diff --git a/chrome/common/pref_names.h b/chrome/common/pref_names.h
index 740971d..3331a0ca 100644
--- a/chrome/common/pref_names.h
+++ b/chrome/common/pref_names.h
@@ -136,6 +136,7 @@ extern const wchar_t kProfilePrefix[];
 
 extern const wchar_t kStabilityExitedCleanly[];
 extern const wchar_t kStabilityStatsVersion[];
+extern const wchar_t kStabilityStatsBuildTime[];
 extern const wchar_t kStabilitySessionEndCompleted[];
 extern const wchar_t kStabilityLaunchCount[];
 extern const wchar_t kStabilityCrashCount[];