Implement ServiceWorkerClient attributes [3/3]

Source/modules/serviceworkers/ServiceWorkerClient.idl

Index: Source/modules/serviceworkers/ServiceWorkerClient.idl
diff --git a/Source/modules/serviceworkers/ServiceWorkerClient.idl b/Source/modules/serviceworkers/ServiceWorkerClient.idl
index a83cbb131cd6bfca2045945c8dda3c91678e117a..90b40fd8978ed1c6d988b9afaa2a07663344ba57 100644
--- a/Source/modules/serviceworkers/ServiceWorkerClient.idl
+++ b/Source/modules/serviceworkers/ServiceWorkerClient.idl
@@ -9,6 +9,10 @@
     GarbageCollected,
     TypeChecking=Interface,
 ] interface ServiceWorkerClient {
+    readonly attribute DOMString visibilityState;
+    readonly attribute boolean focused;
+    readonly attribute USVString url;
+    readonly attribute DOMString frameType;

[mlamouri (slow - plz ping), 2014/12/08 10:41:19]

Do we want to ship those new attributes immediately or do we want to have them
ship with Push? (ie. .focus() is behind the PushMessaging flag)

[Kunihiko Sakamoto, 2014/12/09 02:30:35]

These attributes can have non-Push use cases, so there's no reason to make them
blocked by Push.

There are some ongoing spec discussions though. If any spec issue arises, then
we can add a flag.

     [Custom, RaisesException, CallWith=ExecutionContext] void postMessage(SerializedScriptValue message, optional sequence<Transferable> transfer);
     [RuntimeEnabled=PushMessaging, CallWith=ScriptState] Promise<boolean> focus();
 };