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

components/gcm_driver/instance_id/instance_id_driver_unittest.cc

Index: components/gcm_driver/instance_id/instance_id_driver_unittest.cc
diff --git a/components/gcm_driver/instance_id/instance_id_driver_unittest.cc b/components/gcm_driver/instance_id/instance_id_driver_unittest.cc
index 8997296aca9b1dad49e6749524421ca3094672b6..759299fcd8e60b89999ad1072945df86a2c1d1cb 100644
--- a/components/gcm_driver/instance_id/instance_id_driver_unittest.cc
+++ b/components/gcm_driver/instance_id/instance_id_driver_unittest.cc
@@ -17,6 +17,11 @@
 #include "components/gcm_driver/instance_id/instance_id.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_ANDROID)
+#include "components/gcm_driver/instance_id/instance_id_android.h"
+#include "components/gcm_driver/instance_id/scoped_use_fake_instance_id_android.h"
+#endif  // OS_ANDROID
+
 namespace instance_id {
 
 namespace {
@@ -52,6 +57,7 @@ class InstanceIDDriverTest : public testing::Test {
 
   // testing::Test:
   void SetUp() override;
+  void TearDown() override;
 
   void WaitForAsyncOperation();
 
@@ -85,6 +91,11 @@ class InstanceIDDriverTest : public testing::Test {
   scoped_ptr<FakeGCMDriverForInstanceID> gcm_driver_;
   scoped_ptr<InstanceIDDriver> driver_;
 
+#if defined(OS_ANDROID)
+  InstanceIDAndroid::ScopedBlockOnAsyncTasksForTesting block_async_;
+  ScopedUseFakeInstanceIDAndroid use_fake_;
+#endif  // OS_ANDROID
+
   std::string id_;
   base::Time creation_time_;
   std::string token_;
@@ -109,6 +120,8 @@ void InstanceIDDriverTest::SetUp() {
   RecreateInstanceIDDriver();
 }
 
+void InstanceIDDriverTest::TearDown() {}
+
 void InstanceIDDriverTest::RecreateInstanceIDDriver() {
   driver_.reset(new InstanceIDDriver(gcm_driver_.get()));
 }