QmlProfiler: manage server-side start tracing message

also
QmlProfiler: refactor eventlist state

If unexpected data is received, assuming server stopped profiling.
Also, introducing a eventlist state instead of relying on
signals sent around.  This is part of a coming bigger patch
where the profiler client is refactored.

Change-Id: Ibed9007903956daf03cc0fcb90f77b5ad2d3cf90
Reviewed-by: Kai Koehne <kai.koehne@nokia.com>

src/plugins/qmlprofiler/qml/Label.qml

@@ -81,12 +81,18 @@ Item {
     Connections {
         target: qmlEventList
         onReloadDetailLabels: getDescriptions();
-        onDataReady: getDescriptions();
-        onDataClear: {
-            descriptions = [];
-            eventIds = [];
-            extdescriptions = [];
-            updateHeight();
+        onStateChanged: {
+            // Empty
+            if (qmlEventList.getCurrentStateFromQml() == 0) {
+                descriptions = [];
+                eventIds = [];
+                extdescriptions = [];
+                updateHeight();
+            } else
+            // Done
+            if (qmlEventList.getCurrentStateFromQml() == 3) {
+                getDescriptions();
+            }
         }
     }