Adding error handling to the connection flow.

remoting/ios/app/session_error_view.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef REMOTING_IOS_SESSON_ERROR_VIEW_H_
+#define REMOTING_IOS_SESSON_ERROR_VIEW_H_
+
+#import <UIKit/UIKit.h>
+
+@protocol SessionErrorViewDelegate<NSObject>

[Yuwei, 2017/07/05 21:43:42]

The name seems a bit confusing if what it does is just showing the reconnect
button. X_X If later we want to add the error text here then I think the name
will be fine...

[nicholss, 2017/07/06 20:49:02]

I think I will rename it to SessonReconnectView and add an error message
component if needed later.

+
+// Notifies the delegate that the user tapped the reconnect button.
+@optional
+- (void)didTapReconnect;
+
+@end
+
+// This view is the container for a session connection error. It will display a
+// reconnect button.
+@interface SessionErrorView : UIView
+
+// This delegate will handle interactions on the view.
+@property(weak, nonatomic) id<SessionErrorViewDelegate> delegate;
+
+@end
+
+#endif  // REMOTING_IOS_SESSON_ERROR_VIEW_H_