Turn ArcSupportHost from Observer model to Delegate

chrome/browser/chromeos/arc/arc_support_host.h

Index: chrome/browser/chromeos/arc/arc_support_host.h
diff --git a/chrome/browser/chromeos/arc/arc_support_host.h b/chrome/browser/chromeos/arc/arc_support_host.h
index c645e59073561f2a658f440d7f8590944b432354..870ad9187e5d4728309c5c41904c8503791a59ce 100644
--- a/chrome/browser/chromeos/arc/arc_support_host.h
+++ b/chrome/browser/chromeos/arc/arc_support_host.h
@@ -44,26 +44,55 @@ class ArcSupportHost : public arc::ArcSupportMessageHost::Observer,
     SIGN_IN_UNKNOWN_ERROR,
   };
 
-  // Observer to notify UI event.
-  class Observer {
+  // Delegate to handle manual authentication related events. The life cycle of

[Luis Héctor Chávez, 2017/05/12 15:41:30]

All the "The life cycle of the instance..." comments are maybe unnecessary,
since they are responsible for their own lifetime.

[victorhsieh0, 2017/05/12 18:31:55]

Removed, but add extra comment in the relevant code, which implicitly relies on
the pointer availability.

+  // the instance is as short as the manual authentication process.
+  class AuthDelegate {
    public:
-    virtual ~Observer() = default;
+    virtual ~AuthDelegate() = default;
 
-    // Called when the ARC support window is closed.
-    virtual void OnWindowClosed() {}
+    // Called when LSO auth token fetch is successfully completed.
+    virtual void OnAuthSucceeded(const std::string& auth_code) = 0;
+
+    // Called when LSO auth token fetch has failed.
+    virtual void OnAuthFailed() = 0;
+
+    // Called when "RETRY" button on the error page is clicked during
+    // authentication.
+    virtual void OnAuthRetry() = 0;
+  };
+
+  // Delegate to handle manual authentication related events. The life cycle of
+  // the instance is as short as the terms of service negotiation.
+  class TermsOfServiceDelegate {
+   public:
+    virtual ~TermsOfServiceDelegate() = default;
 
-    // Called when the user press AGREE button on ToS page.
+    // Called when the user press AGREE button on terms of service page.
     virtual void OnTermsAgreed(bool is_metrics_enabled,
                                bool is_backup_and_restore_enabled,
-                               bool is_location_service_enabled) {}
+                               bool is_location_service_enabled) = 0;
 
-    // Called when LSO auth token fetch is successfully completed.
-    virtual void OnAuthSucceeded(const std::string& auth_code) {}
+    // Called when the user rejects the terms of service or close the page.
+    virtual void OnTermsRejected() = 0;
 
-    // Called when LSO auth token fetch has failed.
-    virtual void OnAuthFailed() {}
+    // Called when "RETRY" button on the error page is clicked during terms of
+    // service negotiation.
+    virtual void OnTermsRetry() = 0;

[Luis Héctor Chávez, 2017/05/12 15:41:31]

OnTermsRetried? OnTermsRetryClicked? to be consistent with the OnObjectVerbed
pattern in the rest of the method names. Same in L61.

[victorhsieh0, 2017/05/12 18:31:55]

Done.

+  };
 
-    // Called when "RETRY" button on the error page is clicked.
+  class ErrorDelegate {

[Luis Héctor Chávez, 2017/05/12 15:41:31]

Comment? At least mention that this is the "fallback" delegate that will be
invoked only if there is no more specific delegate.

[victorhsieh0, 2017/05/12 18:31:55]

Done.

+   public:
+    virtual ~ErrorDelegate() = default;
+
+    // Called when the opt-in process is aborted. This currently happens when
+    // the ARC support window is closed (except when when the terms of service
+    // negotiation is ongoing, the most specific function in
+    // TermsOfServiceDelegate is called).
+    virtual void OnOptInAborted() {}

[Luis Héctor Chávez, 2017/05/12 15:41:31]

Any reason why this Delegate has implementations, while the other two only have
pure virtual methods?

[victorhsieh0, 2017/05/12 18:31:55]

Done.

+
+    // Called when "RETRY" button on the error page is clicked, except when
+    // terms of service negotiation or manual authentication is onging. In those
+    // cases, the more specific retry function in the other delegates is called.
     virtual void OnRetryClicked() {}
 
     // Called when send feedback button on error page is clicked.
@@ -82,6 +111,10 @@ class ArcSupportHost : public arc::ArcSupportMessageHost::Observer,
   void RemoveObserver(Observer* observer);
   bool HasObserver(Observer* observer);
 
+  void SetAuthDelegate(AuthDelegate* delegate);
+  void SetTermsOfServiceDelegate(TermsOfServiceDelegate* delegate);
+  void SetErrorDelegate(ErrorDelegate* delegate);
+
   // Called when the communication to arc_support Chrome App is ready.
   void SetMessageHost(arc::ArcSupportMessageHost* message_host);
 
@@ -166,6 +199,9 @@ class ArcSupportHost : public arc::ArcSupportMessageHost::Observer,
   RequestOpenAppCallback request_open_app_callback_;
 
   base::ObserverList<Observer> observer_list_;
+  AuthDelegate* auth_delegate_ = nullptr;           // not owned
+  TermsOfServiceDelegate* tos_delegate_ = nullptr;  // not owned
+  ErrorDelegate* error_delegate_ = nullptr;         // not owned
 
   // True, if ARC support app is requested to start, but the connection is not
   // yet established. Reset to false, when the app is started and the