📰 The Status card reports disabled sync states

components/ntp_snippets/ntp_snippets_service.h

Index: components/ntp_snippets/ntp_snippets_service.h
diff --git a/components/ntp_snippets/ntp_snippets_service.h b/components/ntp_snippets/ntp_snippets_service.h
index fad27ab7e665d649fbdd8dccb2234d728026a086..1ce509c5a38536fbea7282f2236805ec1eb94186 100644
--- a/components/ntp_snippets/ntp_snippets_service.h
+++ b/components/ntp_snippets/ntp_snippets_service.h
@@ -26,6 +26,7 @@
 
 class PrefRegistrySimple;
 class PrefService;
+class SigninManagerBase;
 
 namespace base {
 class Value;
@@ -49,11 +50,19 @@ class SyncService;
 
 namespace ntp_snippets {
 
-enum class DisabledReason {
+// A Java counterpart will be generated for this enum.
+// GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.ntp.snippets

[noyau (Ping after 24h), 2016/06/21 14:28:55]

This is only true for android, please amend the comment to make this obvious. I
would argue that this comment should not be here in the first place. Is this
some kind of automated process generating this java code?

[dgn, 2016/06/21 15:47:39]

Yes, the java_cpp_enum I added to the BUILD.gn file does that. It runs only on
android builds.

+enum class DisabledReason : int {
   // Snippets are enabled
   NONE,
   // Snippets have been disabled as part of the service configuration.
   EXPLICITLY_DISABLED,
+  // The user is not signed in, and the service requires it to be enabled.
+  SIGNED_OUT,
+  // Sync is not enabled, and the service requires it to be enabled.
+  SYNC_DISABLED,
+  // The service requires passphrase encryption to be disabled.
+  PASSPHRASE_ENCRYPTION_ENABLED,

[noyau (Ping after 24h), 2016/06/21 14:28:55]

To be honest I don't like the idea of adding to this class a dependency on
signin. I was already reluctant when there was a dependency on sync, this makes
it too tightly coupled for my taste.

All this disabling  logic could be handled in a separate class. As it is coded
now I feel this is just increasing coupling for a very small gain codewise. 

Ideally the service should be limited to being a service storing and vending
snippets. The fetcher is the one getting the data to feed into the service. Can
you move this enabling/disabling code somewhere else? This would make the tests
clearer as well as of now I'm having difficulties figuring out which of those
disabled mode are tested.

[dgn, 2016/06/21 15:47:39]

Very valid concern. We are working on some refactoring to the Java/XML side to
better prepare supporting different types of content. Some similar effort should
be made here too, in a way that would be compatible with offline pages for
example, that I think we started working on for Android.

So would it be okay to land the disabling as it is, and I'll send you a design
doc about the refactor and how the component would be with regards to new data
sources?

[dgn, 2016/06/24 20:25:20]

Moved the dependencies to NTPSnippetStatusService. That will be updated again
when markusheintz@'s refactor of the component happens.

[markusheintz_, 2016/06/28 14:22:53]

I agree with Eric that we need to split this into multiple pieces.
I will discuss this with all involved parties.

   // History sync is not enabled, and the service requires it to be enabled.
   HISTORY_SYNC_DISABLED,
   // The sync service is not completely initialized, and the status is unknown.
@@ -76,6 +85,7 @@ class NTPSnippetsService : public KeyedService,
   // (British English person in the US) are not language codes.
   NTPSnippetsService(bool enabled,
                      PrefService* pref_service,
+                     SigninManagerBase* signin_manager,
                      sync_driver::SyncService* sync_service,
                      suggestions::SuggestionsService* suggestions_service,
                      const std::string& application_language_code,
@@ -120,6 +130,10 @@ class NTPSnippetsService : public KeyedService,
     return snippets_fetcher_.get();
   }
 
+  // Returns a reason why the service is disabled, or DisabledReason::NONE
+  // if it's not.
+  DisabledReason disabled_reason() const { return disabled_reason_; }
+
   // (Re)schedules the periodic fetching of snippets. This is necessary because
   // the schedule depends on the time of day.
   void RescheduleFetching();
@@ -147,10 +161,6 @@ class NTPSnippetsService : public KeyedService,
   void AddObserver(NTPSnippetsServiceObserver* observer);
   void RemoveObserver(NTPSnippetsServiceObserver* observer);
 
-  // Returns a reason why the service could be disabled, or DisabledReason::NONE
-  // if it's not.
-  DisabledReason GetDisabledReason() const;
-
   // Returns the maximum number of snippets that will be shown at once.
   static int GetMaxSnippetCountForTesting();
 
@@ -222,6 +232,14 @@ class NTPSnippetsService : public KeyedService,
 
   void LoadingSnippetsFinished();
 
+  // Updates |disabled_reason_| (see |GetNewDisabledReason()|) and notifies
+  // observers of changes if necessary.
+  void UpdateDisabledReason();
+
+  // Utility method that looks at the state of the service and its dependencies
+  // to determine if and why it should be disabled.
+  DisabledReason GetNewDisabledReason() const;
+
   // Returns whether the service should be enabled or disable depending on its
   // internal state and the state of its dependencies.
   State GetStateForDependenciesStatus();
@@ -245,13 +263,12 @@ class NTPSnippetsService : public KeyedService,
 
   State state_;
 
-  // The service was set up to be disabled and should not be enabled by any
-  // state change. We track this to make sure we clear scheduled tasks, which
-  // persist even when Chrome is stopped.
-  bool explicitly_disabled_;
+  DisabledReason disabled_reason_;
 
   PrefService* pref_service_;
 
+  SigninManagerBase* signin_manager_;
+
   sync_driver::SyncService* sync_service_;
 
   // The observer for the SyncService. When the sync state changes,
@@ -309,9 +326,10 @@ class NTPSnippetsServiceObserver {
   virtual void NTPSnippetsServiceLoaded() = 0;
   // Sent when the service is shutting down.
   virtual void NTPSnippetsServiceShutdown() = 0;
-  // Sent when the service has been disabled. Can be from explicit user action
-  // or because a requirement (e.g. History Sync) is not fulfilled anymore.
-  virtual void NTPSnippetsServiceDisabled() = 0;
+  // Sent when the state of the service is changing. Something changed in its
+  // dependencies so it's notifying observers about incoming data changes.
+  // If the service might be enabled, DisabledReason::NONE will be provided.
+  virtual void NTPSnippetsServiceDisabledReasonChanged(DisabledReason) = 0;
 
  protected:
   virtual ~NTPSnippetsServiceObserver() {}