ARA: Fix plugins in Logic by making the DocumentController not inherit from Timer

A Timer will only be created for the analysis task when necessary. This
ensures that the ScopedJuceInitialiser_GUI member inside the
DocumentController is initialised before a Timer instance is even
created.

modules/juce_audio_processors/utilities/ARA/juce_ARADocumentController.cpp

@@ -26,8 +26,31 @@
 namespace juce
 {
 
-class ARADocumentControllerSpecialisation::ARADocumentControllerImpl  : public ARADocumentController,
-                                                                        private juce::Timer
+class SimpleTimer final : private Timer
+{
+public:
+    SimpleTimer (int frequencyHz, std::function<void()> callbackIn)
+        : callback (std::move (callbackIn))
+    {
+        jassert (callback);
+        startTimerHz (frequencyHz);
+    }
+
+    ~SimpleTimer() override
+    {
+        stopTimer();
+    }
+
+private:
+    void timerCallback() override
+    {
+        callback();
+    }
+
+    std::function<void()> callback;
+};
+
+class ARADocumentControllerSpecialisation::ARADocumentControllerImpl  : public ARADocumentController
 {
 public:
     ARADocumentControllerImpl (const ARA::PlugIn::PlugInEntry* entry,
@@ -204,10 +227,6 @@ protected:
     void didUpdatePlaybackRegionProperties (ARA::PlugIn::PlaybackRegion* playbackRegion) noexcept override;
     void willDestroyPlaybackRegion (ARA::PlugIn::PlaybackRegion* playbackRegion) noexcept override;
 
-    //==============================================================================
-    // juce::Timer overrides
-    void timerCallback() override;
-
 public:
     //==============================================================================
     /** @internal */
@@ -248,6 +267,9 @@ private:
     std::atomic<bool> internalAnalysisProgressIsSynced { true };
     ScopedJuceInitialiser_GUI libraryInitialiser;
     int activeAudioSourcesCount = 0;
+    std::optional<SimpleTimer> analysisTimer;
+
+    void analysisTimerCallback();
 
     //==============================================================================
     template <typename ModelObject, typename Function, typename... Ts>
@@ -363,10 +385,10 @@ void ARADocumentControllerSpecialisation::ARADocumentControllerImpl::didEndEditi
 {
     notifyListeners (&ARADocument::Listener::didEndEditing, static_cast<ARADocument*> (getDocument()));
 
-    if (isTimerRunning() && (activeAudioSourcesCount == 0))
-        stopTimer();
-    else if (! isTimerRunning() && (activeAudioSourcesCount > 0))
-        startTimerHz (20);
+    if (activeAudioSourcesCount == 0)
+        analysisTimer.reset();
+    else if (! analysisTimer.has_value() && (activeAudioSourcesCount > 0))
+        analysisTimer.emplace (20, [this] { analysisTimerCallback(); });
 }
 
 void ARADocumentControllerSpecialisation::ARADocumentControllerImpl::willNotifyModelUpdates() noexcept
@@ -760,7 +782,7 @@ namespace ModelUpdateControllerProgressAdapter
     }
 }
 
-void ARADocumentControllerSpecialisation::ARADocumentControllerImpl::timerCallback()
+void ARADocumentControllerSpecialisation::ARADocumentControllerImpl::analysisTimerCallback()
 {
     if (! internalAnalysisProgressIsSynced.exchange (true, std::memory_order_release))
         for (auto& audioSource : getDocument()->getAudioSources())