Replace "nested message loop" with "nested run loop" in comments.

Following https://codereview.chromium.org/2818533003/

BUG=703346
[email protected]

Review-Url: https://codereview.chromium.org/2828913003
Cr-Commit-Position: refs/heads/master@{#469674}
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index fae2f71..562caa37 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -1344,7 +1344,7 @@
   shutting_down_ = true;
 #if BUILDFLAG(ENABLE_PRINTING)
   // Wait for the pending print jobs to finish. Don't do this later, since
-  // this might cause a nested message loop to run, and we don't want pending
+  // this might cause a nested run loop to run, and we don't want pending
   // tasks to run once teardown has started.
   print_job_manager_->Shutdown();
 #endif