chrome://snippets-internals page for debugging NTP snippets.

chrome/chrome_browser_ui.gypi

Index: chrome/chrome_browser_ui.gypi
diff --git a/chrome/chrome_browser_ui.gypi b/chrome/chrome_browser_ui.gypi
index 7f78cf852670f3de55c5da128e7cb9bb1138644c..020910fe7d5f97eb69cfbb65fb1f55742f7df919 100644
--- a/chrome/chrome_browser_ui.gypi
+++ b/chrome/chrome_browser_ui.gypi
@@ -501,6 +501,10 @@
       'browser/ui/webui/popular_sites_internals_message_handler.h',
       'browser/ui/webui/popular_sites_internals_ui.cc',
       'browser/ui/webui/popular_sites_internals_ui.h',
+      'browser/ui/webui/snippets_internals_message_handler.cc',
+      'browser/ui/webui/snippets_internals_message_handler.h',
+      'browser/ui/webui/snippets_internals_ui.cc',
+      'browser/ui/webui/snippets_internals_ui.h',
     ],
     # Cross-platform ash sources.
     'chrome_browser_ui_ash_sources': [