TaskTree: Introduce withTimeout()

Make it available for Group or CustomTask items.

Note, that when withTimeout() is used, the total
number of tasks grows by one.

Change-Id: Idc71737ba66b92bdc4bf17599c793b1127d22f5e
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/libs/solutions/tasking/tasktree.h

@@ -187,6 +187,8 @@ protected:
     static TaskItem groupHandler(const GroupHandler &handler) { return TaskItem({handler}); }
     static TaskItem parallelLimit(int limit) { return TaskItem({{}, limit}); }
     static TaskItem workflowPolicy(WorkflowPolicy policy) { return TaskItem({{}, {}, policy}); }
+    static TaskItem withTimeout(const TaskItem &item, std::chrono::milliseconds timeout,
+                                const GroupEndHandler &handler = {});
 
 private:
     Type m_type = Type::Group;
@@ -216,6 +218,11 @@ public:
     using TaskItem::parallelLimit;  // Default: 1 (sequential). 0 means unlimited (parallel).
     using TaskItem::workflowPolicy; // Default: WorkflowPolicy::StopOnError.
 
+    TaskItem withTimeout(std::chrono::milliseconds timeout,
+                         const GroupEndHandler &handler = {}) const {
+        return TaskItem::withTimeout(*this, timeout, handler);
+    }
+
 private:
     template<typename SetupHandler>
     static GroupSetupHandler wrapGroupSetup(SetupHandler &&handler)
@@ -329,6 +336,11 @@ public:
         return *this;
     }
 
+    TaskItem withTimeout(std::chrono::milliseconds timeout,
+                         const GroupEndHandler &handler = {}) const {
+        return TaskItem::withTimeout(*this, timeout, handler);
+    }
+
 private:
     template<typename SetupFunction>
     static TaskItem::TaskSetupHandler wrapSetup(SetupFunction &&function) {