[ios] Adds code for Omaha and the upgrade center.

ios/chrome/browser/upgrade/upgrade_center.h

+// Copyright (c) 2012 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 IOS_CHROME_BROWSER_UPGRADE_UPGRADE_CENTER_H_
+#define IOS_CHROME_BROWSER_UPGRADE_UPGRADE_CENTER_H_
+
+#import <UIKit/UIKit.h>
+
+#include "ios/chrome/browser/upgrade/upgrade_recommended_details.h"
+
+@class UpgradeCenter;
+
+namespace infobars {
+class InfoBarManager;
+}
+
+@protocol UpgradeCenterClientProtocol
+@required

[sdefresne, 2016/12/14 11:50:56]

nit: @required is the default, please remove

[rohitrao (ping after 24h), 2016/12/14 13:26:33]

Done.

+// This is expected to call -addInfoBarToHelper:forTabId: for each tab to place
+// the infobars in the UI. The client must not unregister itself while in this
+// method.
+- (void)showUpgrade:(UpgradeCenter*)center;
+

[sdefresne, 2016/12/14 11:50:56]

nit: remove blank line

[rohitrao (ping after 24h), 2016/12/14 13:26:33]

Added a blank line above instead.

+@end
+
+@interface UpgradeCenter : NSObject
+
+// Returns the singleton instance of the class.
++ (UpgradeCenter*)sharedInstance;
+
+// Register a client for the UpgradeCenter. The clients are not retained,

[sdefresne, 2016/12/14 11:50:56]

nit: Registers?

[rohitrao (ping after 24h), 2016/12/14 13:26:33]

Done.

+// unregisterClient: must be called before the object goes away.
+- (void)registerClient:(id<UpgradeCenterClientProtocol>)client;
+
+// Unregister a client.

[sdefresne, 2016/12/14 11:50:56]

nit: Unregisters?

[rohitrao (ping after 24h), 2016/12/14 13:26:33]

Done.

+- (void)unregisterClient:(id<UpgradeCenterClientProtocol>)client;
+
+// For the client to call when -showUpgrade: is called or when a new tab is
+// created. The infobar will not be created if is already there or if there is

[sdefresne, 2016/12/14 11:50:56]

nit: "if is" -> "if it is"

[rohitrao (ping after 24h), 2016/12/14 13:26:33]

Done.

+// no need to do so.
+- (void)addInfoBarToManager:(infobars::InfoBarManager*)infoBarManager
+                   forTabId:(NSString*)tabId;
+
+// For the UpgradeCenter to make the distinction between an infobar closed by
+// the user directly and an infobar dismissed because the Tab it is on is
+// removed.
+- (void)tabWillClose:(NSString*)tabId;
+
+// Called when a notification is received from one of the upgrade mechanism.
+- (void)upgradeNotificationDidOccur:(const UpgradeRecommendedDetails&)details;
+
+@end
+
+@interface UpgradeCenter (UsedForTests)
+// Reset everything (forget clients, remove the infobar everywhere...)
+- (void)resetForTests;
+// Simulate the minimum display interval having elapsed.
+- (void)setLastDisplayToPast;
+@end
+
+#endif  // IOS_CHROME_BROWSER_UPGRADE_UPGRADE_CENTER_H_