Add browsertest that zoom is preserved on reload

content/test/BUILD.gn

Index: content/test/BUILD.gn
diff --git a/content/test/BUILD.gn b/content/test/BUILD.gn
index f8bfe0d02aaeca529ca1f0dee4e59e878a922ba3..68cd06cf48d6a62d63ea84a67452ae1db17254d1 100644
--- a/content/test/BUILD.gn
+++ b/content/test/BUILD.gn
@@ -584,7 +584,6 @@ test("content_browsertests") {
     "../browser/generic_sensor_browsertest.cc",
     "../browser/gpu/gpu_ipc_browsertests.cc",
     "../browser/host_zoom_map_impl_browsertest.cc",
-    "../browser/iframe_zoom_browsertest.cc",
     "../browser/indexed_db/indexed_db_browsertest.cc",
     "../browser/indexed_db/mock_browsertest_indexed_db_class_factory.cc",
     "../browser/indexed_db/mock_browsertest_indexed_db_class_factory.h",
@@ -645,6 +644,7 @@ test("content_browsertests") {
     "../browser/web_contents/web_contents_view_aura_browsertest.cc",
     "../browser/webkit_browsertest.cc",
     "../browser/webui/web_ui_mojo_browsertest.cc",
+    "../browser/zoom_browsertest.cc",
     "../child/site_isolation_stats_gatherer_browsertest.cc",
     "../renderer/accessibility/render_accessibility_impl_browsertest.cc",
     "../renderer/gin_browsertest.cc",