Retrieve client_id from GoogleUpdateSettings when its missing from Local State.

chrome/browser/metrics/metrics_services_manager.cc

Index: chrome/browser/metrics/metrics_services_manager.cc
diff --git a/chrome/browser/metrics/metrics_services_manager.cc b/chrome/browser/metrics/metrics_services_manager.cc
index 8278913da7da438199e2c1b3f363649bc54148d3..360a4d88b9b2d47ce3610635b1223405184e7ca4 100644
--- a/chrome/browser/metrics/metrics_services_manager.cc
+++ b/chrome/browser/metrics/metrics_services_manager.cc
@@ -4,12 +4,17 @@
 
 #include "chrome/browser/metrics/metrics_services_manager.h"
 
+#include <string>
+
 #include "base/command_line.h"
+#include "base/guid.h"
+#include "base/logging.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/metrics/chrome_metrics_service_client.h"
 #include "chrome/browser/metrics/variations/variations_service.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
+#include "chrome/installer/util/google_update_settings.h"
 #include "components/metrics/metrics_service.h"
 #include "components/metrics/metrics_state_manager.h"
 #include "components/rappor/rappor_service.h"
@@ -18,6 +23,47 @@
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #endif
 
+namespace {
+
+// Attempts to retrieve |client_id| and |installation_date| backed up in
+// GoogleUpdateSettings. Returns true on success retrieving at least the
+// |client_id|.
+bool RetrieveClientInfo(std::string* client_id, int64* installation_date) {
+  DCHECK(client_id);
+  DCHECK(installation_date);
+  bool result =
+      GoogleUpdateSettings::RetrieveMetricsInfo(client_id, installation_date);
+
+  // Prior to 2014-07, the client ID was stripped of its dashes before being
+  // saved, migrate back to a proper GUID if this is the case. This migration

[Ilya Sherman, 2014/07/08 01:10:21]

nit: "saved, migrate" -> "saved. Migrate"

[gab, 2014/07/09 19:16:59]

Done.

+  // code below can be removed in M41+.
+  const size_t kGUIDLengthWithoutDashes = 32U;
+  if (result && client_id->length() == kGUIDLengthWithoutDashes) {
+    DCHECK(client_id->find('-') == std::string::npos);
+
+    std::string client_id_with_dashes;
+    client_id_with_dashes.reserve(kGUIDLengthWithoutDashes + 4U);
+    std::string::const_iterator client_id_it = client_id->begin();
+    for (size_t i = 0; i < kGUIDLengthWithoutDashes + 4U; ++i) {
+      if (i == 8U || i == 13U || i == 18U || i == 23U) {
+        client_id_with_dashes.push_back('-');
+      } else {
+        client_id_with_dashes.push_back(*(client_id_it++));

[Ilya Sherman, 2014/07/08 01:10:21]

nit: I'd prefer that you separate out reading from the iterator and incrementing
it onto two separate lines.

[gab, 2014/07/09 19:16:59]

Done.

+      }
+    }
+    DCHECK(client_id_it == client_id->end());
+    client_id->assign(client_id_with_dashes);
+  }
+
+  // The GUID retrieved (and possibly fixed above) should be valid unless
+  // retrieval failed.
+  DCHECK(base::IsValidGUID(*client_id) || !result);
+
+  return result;
+}
+
+}  // namespace
+
 MetricsServicesManager::MetricsServicesManager(PrefService* local_state)
     : local_state_(local_state) {
   DCHECK(local_state);
@@ -70,7 +116,9 @@ metrics::MetricsStateManager* MetricsServicesManager::GetMetricsStateManager() {
     metrics_state_manager_ = metrics::MetricsStateManager::Create(
         local_state_,
         base::Bind(&MetricsServicesManager::IsMetricsReportingEnabled,
-                   base::Unretained(this)));
+                   base::Unretained(this)),
+        base::Bind(&GoogleUpdateSettings::SaveMetricsInfo),
+        base::Bind(&RetrieveClientInfo));
   }
   return metrics_state_manager_.get();
 }