QML Debugger: Restore the ability to set breakpoint on all files.

The agent is only attached when creator request it.  But this may occurs
After some scripts have been initialized. Which mean we do not get the
scriptLoad call.

src/tools/qml/qmlviewer/jsdebuggeragent.cpp

@@ -130,12 +130,16 @@ void JSDebuggerAgent::positionChange(qint64 scriptId,
     // check breakpoints
     if (!breakpointList.isEmpty()) {
         QHash<qint64, QString>::const_iterator it = filenames.constFind(scriptId);
-        if (it != filenames.constEnd()) {
-            QPair<QString, qint32> key = qMakePair(*it, lineNumber);
-            if (breakpointList.contains(key)) {
-                stopped();
-                return;
-            }
+        if (it == filenames.constEnd()) {
+            // It is possible that the scripts are loaded before the agent is attached
+            QString filename = QUrl(QScriptContextInfo(engine()->currentContext()).fileName()).toLocalFile();
+            QPair<QString, qint32> key = qMakePair(filename, lineNumber);
+            it = filenames.insert(scriptId, filename);
+        }
+        QPair<QString, qint32> key = qMakePair(*it, lineNumber);
+        if (breakpointList.contains(key)) {
+            stopped();
+            return;
         }
     }