Correctly report extension renderer launch counts in system profile.

BUG=621120

Review-Url: https://codereview.chromium.org/2164023002
Cr-Commit-Position: refs/heads/master@{#406606}
diff --git a/components/metrics/stability_metrics_helper.cc b/components/metrics/stability_metrics_helper.cc
index 8adcb226..af7f1b4f 100644
--- a/components/metrics/stability_metrics_helper.cc
+++ b/components/metrics/stability_metrics_helper.cc
@@ -122,10 +122,11 @@
     local_state_->SetInteger(prefs::kStabilityRendererHangCount, 0);
   }
 
-  count = local_state_->GetInteger(prefs::kStabilityRendererLaunchCount);
+  count =
+      local_state_->GetInteger(prefs::kStabilityExtensionRendererLaunchCount);
   if (count) {
-    stability_proto->set_renderer_launch_count(count);
-    local_state_->SetInteger(prefs::kStabilityRendererLaunchCount, 0);
+    stability_proto->set_extension_renderer_launch_count(count);
+    local_state_->SetInteger(prefs::kStabilityExtensionRendererLaunchCount, 0);
   }
 }