MacViews: Enable views based External Protocol dialog behind secondary-ui-md flag.

chrome/browser/ui/BUILD.gn

Index: chrome/browser/ui/BUILD.gn
diff --git a/chrome/browser/ui/BUILD.gn b/chrome/browser/ui/BUILD.gn
index d535c119a001e5ec5e9946a02703de873c088ce0..2b39c1fdbe0c3e1cc8f2b41f51f069a71175e9e4 100644
--- a/chrome/browser/ui/BUILD.gn
+++ b/chrome/browser/ui/BUILD.gn
@@ -1546,10 +1546,6 @@ split_static_library("ui") {
       ]
     } else if (!is_mac || mac_views_browser) {
       sources += [
-        "external_protocol_dialog_delegate.cc",
-        "external_protocol_dialog_delegate.h",
-        "views/external_protocol_dialog.cc",
-        "views/external_protocol_dialog.h",
         "views/frame/opaque_browser_frame_view.cc",
         "views/frame/opaque_browser_frame_view.h",
         "views/frame/opaque_browser_frame_view_layout.cc",
@@ -1569,6 +1565,15 @@ split_static_library("ui") {
       ]
     }
 
+    if (!is_chromeos) {
+      sources += [
+        "external_protocol_dialog_delegate.cc",
+        "external_protocol_dialog_delegate.h",
+        "views/external_protocol_dialog.cc",
+        "views/external_protocol_dialog.h",
+      ]
+    }
+
     # These files do Gtk+-based theming, but Gtk+ is not available on
     # Ozone builds, or on common environments where Ozone will be used.
     #
@@ -2687,7 +2692,8 @@ split_static_library("ui") {
         "cocoa/extensions/windowed_install_dialog_controller.h",
         "cocoa/extensions/windowed_install_dialog_controller.mm",
         "cocoa/external_protocol_dialog.h",
-        "cocoa/external_protocol_dialog.mm",
+        "cocoa/external_protocol_dialog_cocoa.mm",
+        "cocoa/external_protocol_dialog_views_mac.mm",
         "cocoa/fast_resize_view.h",
         "cocoa/fast_resize_view.mm",
         "cocoa/find_bar/find_bar_bridge.h",