Task: Add clear method

Avoid needless increments of the task id counter for Task().

Change-Id: I6243b4fe9e8fd91653e236722282fa8f8a9ed82d
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/projectexplorer/task.cpp

@@ -59,6 +59,17 @@ void Task::addMark(TextEditor::BaseTextMark *mark)
 bool Task::isNull() const
 { return taskId == 0; }
 
+void Task::clear()
+{
+    taskId = 0;
+    description.clear();
+    file = Utils::FileName();
+    line = -1;
+    movedLine = -1;
+    category = Core::Id();
+    type = Task::Unknown;
+}
+
 //
 // functions
 //

src/plugins/projectexplorer/task.h

@@ -57,6 +57,7 @@ public:
          const Utils::FileName &file_, int line_, const Core::Id &category_);
 
     bool isNull() const;
+    void clear();
 
     unsigned int taskId;
     TaskType type;