Sync more GN unit tests with GYP.

components/constrained_window/BUILD.gn

Index: components/constrained_window/BUILD.gn
diff --git a/components/constrained_window/BUILD.gn b/components/constrained_window/BUILD.gn
index 7b284981e33d4ef1a6d9f934d5afd645a24bf037..01257f8d8d5cda8f8a9344a268fa2e035979e92b 100644
--- a/components/constrained_window/BUILD.gn
+++ b/components/constrained_window/BUILD.gn
@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-static_library("constrained_window") {
+source_set("constrained_window") {
   sources = [
     "constrained_window_views.cc",
     "constrained_window_views.h",
@@ -25,6 +25,7 @@ source_set("unit_tests") {
 
   deps = [
     ":constrained_window",
+    "//components/web_modal:test_support",
     "//ui/views:test_support",
   ]
 }