Move web modal dialog manager files into the constrained_window component.

components/web_modal.gypi

Index: components/web_modal.gypi
diff --git a/components/web_modal.gypi b/components/web_modal.gypi
index cb257daa6473d27115d3a2036b9de87d4c993ceb..6e70071bab480fbff8735532d10b0d1657153c46 100644
--- a/components/web_modal.gypi
+++ b/components/web_modal.gypi
@@ -16,6 +16,10 @@
         '../content/content.gyp:content_browser',
         '../skia/skia.gyp:skia',
       ],
+      'export_dependent_settings': [
+        # Skia headers are exposed in the public API.
+        '../skia/skia.gyp:skia',
+      ],
       'sources': [
         # Note: sources list duplicated in GN build.
         'web_modal/modal_dialog_host.cc',