Adding sampling support to installer crash reporter client.

chrome/install_static/install_util.h

Index: chrome/install_static/install_util.h
diff --git a/chrome/install_static/install_util.h b/chrome/install_static/install_util.h
index 4ddcbfdad20ffeb4714f7043d6f14a2f443a7757..1aece7c27199fcecdfae42550204d7dae2952a12 100644
--- a/chrome/install_static/install_util.h
+++ b/chrome/install_static/install_util.h
@@ -34,6 +34,13 @@ extern const wchar_t kRegPathClientState[];
 extern const wchar_t kRegPathClientStateMedium[];
 extern const wchar_t kRegPathChromePolicy[];
 extern const wchar_t kRegApField[];
+// Registry key to store the stats/crash sampling state of Chrome. If set to 1,
+// stats and crash reports will be uploaded in line with the user's consent,
+// otherwise, uploads will be disabled. It is used to sample clients, to reduce
+// server load for metics and crashes. This is controlled by the
+// MetricsReporting feature in chrome_metrics_services_manager_client.cc and is
+// written when metrics services are started up and when consent changes.
+extern const wchar_t kRegValueChromeStatsSample[];
 // Used to retrieve consent for uploading crashes and metrics.
 extern const wchar_t kRegValueUsageStats[];
 extern const wchar_t kUninstallArgumentsField[];