[ios] Implements support for chrome://prefs-internals.

BUG=1006711

Change-Id: I16e839f2ac419d051a0f2ca1b40f7ad1c8362966
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1819241
Reviewed-by: Justin Cohen <[email protected]>
Commit-Queue: Rohit Rao <[email protected]>
Cr-Commit-Position: refs/heads/master@{#698873}
diff --git a/ios/chrome/browser/ui/webui/BUILD.gn b/ios/chrome/browser/ui/webui/BUILD.gn
index c275493..8b3e6b6 100644
--- a/ios/chrome/browser/ui/webui/BUILD.gn
+++ b/ios/chrome/browser/ui/webui/BUILD.gn
@@ -22,6 +22,8 @@
     "mojo_web_ui_ios_controller.h",
     "ntp_tiles_internals_ui.cc",
     "ntp_tiles_internals_ui.h",
+    "prefs_internals_ui.cc",
+    "prefs_internals_ui.h",
     "suggestions_ui.cc",
     "suggestions_ui.h",
     "terms_ui.h",