Add renderer launch count to stability metrics.

components/metrics/stability_metrics_helper.h

Index: components/metrics/stability_metrics_helper.h
diff --git a/components/metrics/stability_metrics_helper.h b/components/metrics/stability_metrics_helper.h
index 42a9ca202174666e9c8ac389eb49b85ed1354087..87f8f400f1962a53b5b044ca2328b4b06fc52f7b 100644
--- a/components/metrics/stability_metrics_helper.h
+++ b/components/metrics/stability_metrics_helper.h
@@ -36,10 +36,13 @@ class StabilityMetricsHelper {
   void LogLoadStarted();
 
   // Records a renderer process crash.
-  void LogRendererCrash(bool was_exception_process,
+  void LogRendererCrash(bool was_extension_process,
                         base::TerminationStatus status,
                         int exit_code);
 
+  // Records that a new renderer process was successfully launched.
+  void LogRendererLaunched(bool was_extension_process);
+
   // Records a renderer process hang.
   void LogRendererHang();