Retrieve client_id from GoogleUpdateSettings when its missing from Local State.

chrome/app/client_util.cc

Index: chrome/app/client_util.cc
diff --git a/chrome/app/client_util.cc b/chrome/app/client_util.cc
index ac6dbfc111bece74b0d214d6430157f94a3d2af1..efb79d57cf6534fb3d4db5ef56d20c0885c696c1 100644
--- a/chrome/app/client_util.cc
+++ b/chrome/app/client_util.cc
@@ -34,6 +34,7 @@
 #include "chrome/installer/util/util_constants.h"
 #include "components/breakpad/app/breakpad_client.h"
 #include "components/breakpad/app/breakpad_win.h"
+#include "components/metrics/client_info.h"
 #include "content/public/app/startup_helper_win.h"
 #include "sandbox/win/src/sandbox.h"
 
@@ -75,14 +76,14 @@ bool PreReadExperimentIsActive() {
 void GetPreReadPopulationAndGroup(double* population, double* group) {
   // By default we use the metrics id for the user as stable pseudo-random
   // input to a hash.
-  std::string metrics_id;
-  GoogleUpdateSettings::LoadMetricsClientId(&metrics_id);
+  scoped_ptr<metrics::ClientInfo> client_info =
+      GoogleUpdateSettings::LoadMetricsClientInfo();
 
-  // If this user has not metrics id, we fall back to a purely random value
-  // per browser session.
+  // If this user has no metrics id, we fall back to a purely random value per
+  // browser session.
   const size_t kLength = 16;
-  std::string random_value(metrics_id.empty() ? base::RandBytesAsString(kLength)
-                                              : metrics_id);
+  std::string random_value(client_info ? client_info->client_id
+                                       : base::RandBytesAsString(kLength));
 
   // To interpret the value as a random number we hash it and read the first 8
   // bytes of the hash as a unit-interval representing a die-toss for being in