[NTP::Push] Add Content Suggestions GCM App Handler

components/ntp_snippets/breaking_news/subscription_manager.cc

Index: components/ntp_snippets/breaking_news/subscription_manager.cc
diff --git a/components/ntp_snippets/breaking_news/subscription_manager.cc b/components/ntp_snippets/breaking_news/subscription_manager.cc
index 8f7dbc9a5b3f6f399f4fa12af234b4ab7530c5f3..01570be2ddee0274479c51c5cc5162a0bc0d146b 100644
--- a/components/ntp_snippets/breaking_news/subscription_manager.cc
+++ b/components/ntp_snippets/breaking_news/subscription_manager.cc
@@ -15,10 +15,12 @@ using internal::SubscriptionJsonRequest;
 SubscriptionManager::SubscriptionManager(
     scoped_refptr<net::URLRequestContextGetter> url_request_context_getter,
     PrefService* pref_service,
-    const GURL& subscribe_url)
+    const GURL& subscribe_url,
+    const GURL& unsubscribe_url)
     : url_request_context_getter_(std::move(url_request_context_getter)),
       pref_service_(pref_service),
-      subscribe_url_(subscribe_url) {}
+      subscribe_url_(subscribe_url),
+      unsubscribe_url_(unsubscribe_url) {}
 
 SubscriptionManager::~SubscriptionManager() = default;
 
@@ -55,7 +57,32 @@ void SubscriptionManager::DidSubscribe(const ntp_snippets::Status& status) {
 }
 
 void SubscriptionManager::Unsubscribe(const std::string& token) {
-  // TODO(mamir): Implement.
+  DCHECK(!unsubscription_request_);

[jkrcal, 2017/06/09 09:10:10]

I find this (and above) a bit subtle to use:
It is not allowed to run concurrent Subscribe / Unsubscribe requests but the
caller will never know when a request is finished.

Why DCHECK and not simply return (e.g. false)?
Is it okay to call Subscribe() before Unsubscribe() finished?

[mamir, 2017/06/09 13:52:58]

As discussed off-review, I have added 3 methods CanSubscribeNow(),
CanUnsubscribeNow(), IsSubscribed()
PTAL

+  unsubscription_token_ = token;
+  SubscriptionJsonRequest::Builder builder;
+  builder.SetToken(token)
+      .SetUrlRequestContextGetter(url_request_context_getter_)
+      .SetUrl(unsubscribe_url_);
+
+  unsubscription_request_ = builder.Build();
+  unsubscription_request_->Start(base::BindOnce(
+      &SubscriptionManager::DidUnsubscribe, base::Unretained(this)));
+}
+
+void SubscriptionManager::DidUnsubscribe(const ntp_snippets::Status& status) {
+  unsubscription_request_.reset();
+
+  switch (status.code) {
+    case ntp_snippets::StatusCode::SUCCESS:
+      // In case of successful unsubscription, clear the previously stored data.
+      // TODO(mamir): clear stored region and language.
+      pref_service_->ClearPref(
+          ntp_snippets::prefs::kContentSuggestionsSubscriptionDataToken);
+      break;
+    default:
+      // TODO(mamir): handle failure.
+      break;
+  }
 }
 
 void SubscriptionManager::RegisterProfilePrefs(PrefRegistrySimple* registry) {