[CRD iOS] Add the host setup instruction page

remoting/ios/facade/remoting_service.h

Index: remoting/ios/facade/remoting_service.h
diff --git a/remoting/ios/facade/remoting_service.h b/remoting/ios/facade/remoting_service.h
index 120e8ce336f939f539d90749c3dd1115be1dd066..af15a60a95d14ed49865b38926f136d89be14aca 100644
--- a/remoting/ios/facade/remoting_service.h
+++ b/remoting/ios/facade/remoting_service.h
@@ -12,10 +12,21 @@
 
 @protocol RemotingAuthentication;
 
+typedef NS_ENUM(NSInteger, HostListState) {
+  // Nobody has requested a host list fetch.
+  HostListStateNotFetched,
+
+  // The host list is currently being fetched.
+  HostListStateFetching,
+
+  // The host list has been fetched.
+  HostListStateFetched,
+};
+
 // Eventing related keys:
 
 // Hosts did update event.
-extern NSString* const kHostsDidUpdate;
+extern NSString* const kHostListStateDidChange;
 // User did update event name.
 extern NSString* const kUserDidUpdate;
 // Map key for UserInfo object.
@@ -37,6 +48,8 @@ extern NSString* const kUserInfo;
 // Returns the current host list.
 @property(nonatomic, readonly) NSArray<HostInfo*>* hosts;
 
+@property(nonatomic, readonly) HostListState hostListState;
+
 // The Chromoting Client Runtime, this holds the threads and other shared
 // resources used by the Chromoting clients
 @property(nonatomic, readonly) remoting::ChromotingClientRuntime* runtime;