ProjectExplorer: Introduce an "essential" flag for RunWorker

An essential RunWorker triggers the whole RunControl to stop if it
spontaneously stops.

Change-Id: Ia05b927e306022e99b45cc8cd7ab9636f4d3c129
Reviewed-by: hjk <hjk@qt.io>

src/plugins/projectexplorer/runconfiguration.cpp

@@ -547,6 +547,7 @@ public:
     int stopWatchdogInterval = 0; // 5000;
     int stopWatchdogTimerId = -1;
     bool supportsReRunning = true;
+    bool essential = false;
 };
 
 enum class RunControlState
@@ -954,6 +955,10 @@ void RunControlPrivate::onWorkerStopped(RunWorker *worker)
     if (state == RunControlState::Finishing || state == RunControlState::Stopping) {
         continueStopOrFinish();
         return;
+    } else if (worker->isEssential()) {
+        debugMessage(workerId + " is essential. Stopping all others.");
+        initiateStop();
+        return;
     }
 
     for (RunWorker *dependent : worker->d->stopDependencies) {
@@ -1701,6 +1706,16 @@ QString RunWorker::userMessageForProcessError(QProcess::ProcessError error, cons
     return msg;
 }
 
+bool RunWorker::isEssential() const
+{
+    return d->essential;
+}
+
+void RunWorker::setEssential(bool essential)
+{
+    d->essential = essential;
+}
+
 void RunWorker::start()
 {
     reportStarted();