Add a chrome://webapks page.

chrome/chrome_paks.gni

Index: chrome/chrome_paks.gni
diff --git a/chrome/chrome_paks.gni b/chrome/chrome_paks.gni
index 1ecd49bff0fefdc3a002e4ee79ac14b12313bfb3..27c28f32ac7d3eedbf38c2cbf346902f75d70412 100644
--- a/chrome/chrome_paks.gni
+++ b/chrome/chrome_paks.gni
@@ -168,6 +168,10 @@ template("chrome_extra_paks") {
       ]
       deps += [ "//extensions:extensions_resources" ]
     }
+    if (is_android) {
+      sources += [ "$root_gen_dir/chrome/webapks_ui_resources.pak" ]
+      deps += [ "//chrome/browser/resources:webapks_ui_resources" ]
+    }
   }
 }