Add a test for Flash Fullscreen from a cross-site subframe.

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index b62091b070f9590cd9fe5a3ed5e96239e2958114..24da05b1d307709fdc6403f09cf7ceb68f67fbcc 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -376,6 +376,10 @@ if (!is_android) {
       "//third_party/zlib/google/test/data/",
       "//tools/metrics/histograms/histograms.xml",
       "$root_out_dir/pyproto/google/",
+      "$root_out_dir/test_case.html",
+      "$root_out_dir/test_case.html.mock-http-headers",
+      "$root_out_dir/test_page.css",
+      "$root_out_dir/test_page.css.mock-http-headers",
       "$root_out_dir/ui_test.pak",
     ]
     if (is_linux || is_win) {