[CRD iOS] Add the host setup instruction page

remoting/ios/app/host_collection_view_cell.mm

 // 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.
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 #import <UIKit/UIKit.h>
 
@@ skipping 31 matching lines @@
     self.backgroundColor = [UIColor clearColor];
     [self commonInit];
   }
   return self;
 }
 
 - (void)commonInit {
   _imageView = [[UIImageView alloc] init];
   _imageView.translatesAutoresizingMaskIntoConstraints = NO;
   _imageView.contentMode = UIViewContentModeCenter;
-  _imageView.alpha = 0.87f;
   _imageView.backgroundColor = RemotingTheme.offlineHostColor;
   _imageView.layer.cornerRadius = kHostCardIconSize / 2.f;
   _imageView.layer.masksToBounds = YES;
   [self.contentView addSubview:_imageView];
 
   // Holds both of the labels.
   _labelView = [[UIView alloc] init];
   _labelView.translatesAutoresizingMaskIntoConstraints = NO;
   [self.contentView addSubview:_labelView];
 
@@ skipping 82 matching lines @@
 #pragma mark - UICollectionReusableView
 
 - (void)prepareForReuse {
   [super prepareForReuse];
   _hostInfo = nil;
   _statusLabel.text = nil;
   _titleLabel.text = nil;
 }
 
 @end