Add options to let mojom targets override their component deps.

mojo/public/cpp/bindings/tests/BUILD.gn

Index: mojo/public/cpp/bindings/tests/BUILD.gn
diff --git a/mojo/public/cpp/bindings/tests/BUILD.gn b/mojo/public/cpp/bindings/tests/BUILD.gn
index 2e6117393d5f3e56b82c5b454036db2673d5b0c3..9931724034f91c52fe26d7f7478d6887e56a751e 100644
--- a/mojo/public/cpp/bindings/tests/BUILD.gn
+++ b/mojo/public/cpp/bindings/tests/BUILD.gn
@@ -53,6 +53,7 @@ source_set("tests") {
     "//mojo/public/cpp/test_support:test_utils",
     "//mojo/public/interfaces/bindings/tests:test_associated_interfaces",
     "//mojo/public/interfaces/bindings/tests:test_export_component",
+    "//mojo/public/interfaces/bindings/tests:test_exported_import",
     "//mojo/public/interfaces/bindings/tests:test_interfaces",
     "//mojo/public/interfaces/bindings/tests:test_interfaces_experimental",
     "//mojo/public/interfaces/bindings/tests:test_struct_traits_interfaces",
@@ -92,6 +93,8 @@ if (!is_ios) {
     deps = [
       "//mojo/public/cpp/bindings",
       "//mojo/public/cpp/system",
+      "//mojo/public/interfaces/bindings/tests:test_export_blink_component",
+      "//mojo/public/interfaces/bindings/tests:test_exported_import_blink",
       "//mojo/public/interfaces/bindings/tests:test_interfaces",
       "//mojo/public/interfaces/bindings/tests:test_interfaces_blink",
       "//mojo/public/interfaces/bindings/tests:test_wtf_types",