Convert Spellcheck host MessageFilter IPC to mojo

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index 860813612cd9e690be6d7057ce049c36e950f6d3..2fdeb2bdb6c2556610b9027d6f516b5d1dd7f7fa 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -3685,11 +3685,14 @@ test("unit_tests") {
     sources += [
       "../browser/spellchecker/spellcheck_custom_dictionary_unittest.cc",
       "../browser/spellchecker/spellcheck_message_filter_platform_mac_unittest.cc",
-      "../browser/spellchecker/spellcheck_message_filter_unittest.cc",
       "../browser/spellchecker/spellcheck_service_unittest.cc",
       "../browser/spellchecker/spelling_service_client_unittest.cc",
       "../tools/convert_dict/convert_dict_unittest.cc",
     ]
+
+    if (!use_browser_spellchecker) {
+      sources += [ "../browser/spellchecker/spellcheck_host_impl_unittest.cc" ]
+    }
   }
 
   if (enable_one_click_signin) {