Add fake for InstanceIDWithSubtype.java, in order to re-use unit test

components/BUILD.gn

Index: components/BUILD.gn
diff --git a/components/BUILD.gn b/components/BUILD.gn
index 2f721dff6437d11c5005db9dbe756709d5f9f85b..c83130452ba7b1575d2f612fa2da76c985d2a66d 100644
--- a/components/BUILD.gn
+++ b/components/BUILD.gn
@@ -148,6 +148,7 @@ test("components_unittests") {
       "//components/favicon_base:unit_tests",
       "//components/gcm_driver:unit_tests",
       "//components/gcm_driver/crypto:unit_tests",
+      "//components/gcm_driver/instance_id:unit_tests",
       "//components/guest_view/browser:unit_tests",
       "//components/history/content/browser:unit_tests",
       "//components/history/core/browser:unit_tests",
@@ -221,6 +222,7 @@ test("components_unittests") {
     isolate_file = "components_unittests.isolate"
 
     deps += [
+      "//components/gcm_driver/instance_id/android:instance_id_driver_java",
       "//components/invalidation/impl",
       "//components/invalidation/impl:java",
       "//components/safe_json",
@@ -232,8 +234,12 @@ test("components_unittests") {
       "//components/web_restrictions:test_support_java",
       "//components/web_restrictions:unit_tests",
       "//content/public/android:content_java",
-      "//content/public/android:content_java",
       "//content/public/browser",
+
+      # Required by //components/gcm_driver/instance_id:unit_tests for
+      # NestedSystemMessageHandler.java
+      "//content/public/test/android:content_java_test_support",
+
       "//net",
       "//ui/android:ui_java",
       "//ui/base",
@@ -251,7 +257,6 @@ test("components_unittests") {
       "//components/audio_modem:unit_tests",
       "//components/copresence:unit_tests",
       "//components/feedback:unit_tests",
-      "//components/gcm_driver/instance_id:unit_tests",
       "//components/proximity_auth:unit_tests",
       "//components/storage_monitor:unit_tests",
       "//components/web_modal:unit_tests",