Move ChromeOS hardware class init out of MetricsService.

chrome/browser/metrics/chrome_metrics_service_client.h

Index: chrome/browser/metrics/chrome_metrics_service_client.h
diff --git a/chrome/browser/metrics/chrome_metrics_service_client.h b/chrome/browser/metrics/chrome_metrics_service_client.h
index 1a33510f0bfba470437672bf14ac9dfc3054faac..4a6c2b5a97978f8c640904facc40823aa29ac8ae 100644
--- a/chrome/browser/metrics/chrome_metrics_service_client.h
+++ b/chrome/browser/metrics/chrome_metrics_service_client.h
@@ -17,6 +17,7 @@
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
+class ChromeOSMetricsProvider;
 class MetricsService;
 
 namespace metrics {
@@ -85,6 +86,10 @@ class ChromeMetricsServiceClient : public metrics::MetricsServiceClient,
 
   content::NotificationRegistrar registrar_;
 
+  // On ChromeOS, holds a weak pointer to the ChromeOSMetricsProvider instance
+  // that has been registered with MetricsService. On other platforms, is NULL.
+  ChromeOSMetricsProvider* chromeos_metrics_provider_;
+
   NetworkStatsUploader network_stats_uploader_;
 
   // Saved callback received from CollectFinalMetrics().