mojo: add some end-to-end shell tests and a new test sample app

mojo/services/test_service/test_service.mojom

Index: mojo/services/test_service/test_service.mojom
diff --git a/mojo/services/test_service/test_service.mojom b/mojo/services/test_service/test_service.mojom
index 1065b20ab30847eca7a74f2ed21f5e31691f6ed4..8e73a3d2bcb392f598630887f0439d4a4aebe978 100644
--- a/mojo/services/test_service/test_service.mojom
+++ b/mojo/services/test_service/test_service.mojom
@@ -4,8 +4,16 @@
 
 module mojo.test {
 
-interface ITestService {
+interface TestService {
+  const string kWelcomeMessagePrefix = "Party like it's ";

[viettrungluu, 2014/06/30 17:08:24]

I'm "surprised" we support const strings; I'm not sure if we should[*] so
perhaps we should avoid using them.

[*] Currently, the mojom bindings generator doesn't do any
validation/escaping/etc. of strings, and we don't need string literals
elsewhere.

[tim (not reviewing), 2014/06/30 22:20:54]

Interesting. I saw a const string in sample_service.mojom and also
https://codereview.chromium.org/268363003, and assumed this was OK.

I can remove it, I was only using it for convenience here, but I could imagine
some services wanting to specify constant strings like this at some point. 

   Ping() => ();
+  GetFriendlyWelcomeMessage(string time_app_url) => (string friendly_welcome);
+  StartMonitoring() => ();

[viettrungluu, 2014/06/30 17:08:24]

Does this really need to have a response?

[tim (not reviewing), 2014/06/30 22:20:54]

It wouldn't if I didn't care about verifying certain things are happening by a
certain point. Otherwise something like

service->StartMonitoring
service->Ping
...
loop->Run

means the pings will always hit the service before the monitoring handshake has
completed, which is fine except that you can't query the (separate) monitoring
service and EXPECT_ that the pings were registered (yet).

So to facilitate testing I opted to make it easy to track progress of the
different steps.  

On 2014/06/30 17:08:24, viettrungluu wrote:

+};
+
+interface TestTimeService {
+  GetPartyTime() => (int64 time_usec);
+  StartMonitoring() => ();
 };
 
 }  // module mojo.test