Initialize SystemTask, DisplayApp and HeartRateTask as global static variable instead of variables on the heap. We don't need them on the heap as we know their size at build time, it'll reduce memory fragmentation and it'll make memory analysis easier.

src/components/datetime/DateTimeController.cpp

@@ -5,9 +5,6 @@
 
 using namespace Pinetime::Controllers;
 
-DateTime::DateTime(System::SystemTask& systemTask) : systemTask {systemTask} {
-}
-
 void DateTime::SetTime(
   uint16_t year, uint8_t month, uint8_t day, uint8_t dayOfWeek, uint8_t hour, uint8_t minute, uint8_t second, uint32_t systickCounter) {
   std::tm tm = {
@@ -70,7 +67,8 @@ void DateTime::UpdateTime(uint32_t systickCounter) {
   // Notify new day to SystemTask
   if (hour == 0 and not isMidnightAlreadyNotified) {
     isMidnightAlreadyNotified = true;
-    systemTask.PushMessage(System::SystemTask::Messages::OnNewDay);
+    if(systemTask != nullptr)
+      systemTask->PushMessage(System::Messages::OnNewDay);
   } else if (hour != 0) {
     isMidnightAlreadyNotified = false;
   }
@@ -104,6 +102,10 @@ const char* DateTime::DayOfWeekShortToStringLow() {
   return DateTime::DaysStringShortLow[(uint8_t) dayOfWeek];
 }
 
+void DateTime::Register(Pinetime::System::SystemTask* systemTask) {
+  this->systemTask = systemTask;
+}
+
 char const* DateTime::DaysStringLow[] = {"--", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
 
 char const* DateTime::DaysStringShortLow[] = {"--", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};