Replace s/NULL/nullptr/ in field initializers used in constructors.

This change has been generated by a clang tool developed for the
go/miracleptr project.

Bug: 1080832
Change-Id: Ie7f428c8ad300db1df95d873668163d0ac719a22
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2231843
Reviewed-by: Kentaro Hara <[email protected]>
Reviewed-by: Bartek Nowierski <[email protected]>
Commit-Queue: Ɓukasz Anforowicz <[email protected]>
Cr-Commit-Position: refs/heads/master@{#776343}
diff --git a/ipc/ipc_mojo_perftest.cc b/ipc/ipc_mojo_perftest.cc
index df562d4..723b96d 100644
--- a/ipc/ipc_mojo_perftest.cc
+++ b/ipc/ipc_mojo_perftest.cc
@@ -42,7 +42,7 @@
  public:
   explicit PerformanceChannelListener(const std::string& label)
       : label_(label),
-        sender_(NULL),
+        sender_(nullptr),
         msg_count_(0),
         msg_size_(0),
         sync_(false),