Do IWYU for ptr_util.h.

Change-Id: Ib96a66eb47bea791f061e1d6da8aadad8037a99d
Reviewed-on: https://pdfium-review.googlesource.com/c/43609
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
diff --git a/fxjs/cjs_global.cpp b/fxjs/cjs_global.cpp
index ecf06f1..a683ed8 100644
--- a/fxjs/cjs_global.cpp
+++ b/fxjs/cjs_global.cpp
@@ -19,6 +19,7 @@
 #include "fxjs/cjs_object.h"
 #include "fxjs/js_define.h"
 #include "fxjs/js_resources.h"
+#include "third_party/base/ptr_util.h"
 
 namespace {