Support uninstalling ARC app from Chrome launcher

components/arc/test/fake_app_instance.cc

Index: components/arc/test/fake_app_instance.cc
diff --git a/components/arc/test/fake_app_instance.cc b/components/arc/test/fake_app_instance.cc
index 8f6fe71498544f4a84cbfd9388c462eb5689dfa5..61a8499e5a4f7eef05e239fb9bbed48739e2a45b 100644
--- a/components/arc/test/fake_app_instance.cc
+++ b/components/arc/test/fake_app_instance.cc
@@ -133,4 +133,9 @@ void FakeAppInstance::CanHandleResolution(const mojo::String& package_name,
   callback.Run(true);
 }
 
+void FakeAppInstance::UninstallApp(const mojo::String& package_name,
+                                   const UninstallAppCallback& callback) {
+  callback.Run(nullptr);

[dcheng, 2016/03/08 02:18:46]

It feels a little funky that you can construct mojo::String from nullptr. Meh.

[victorhsieh0, 2016/03/08 18:02:52]

Yeah, mojo::String can be passed through IPC, so it kind of makes sense to
accept nullptr.  I now made an explicit conversion.

+}
+
 }  // namespace arc