Try to watch local variable in watchwindow-DND, too.

Fix codepath overlooked in
6886e485

 by introducing
a WatchHandler::watchVariable().

Task-number: QTCREATORBUG-8120
Change-Id: Ibab2619754e0006f3c81810a6bfdf758261c169e
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/debugger/debuggerplugin.cpp

@@ -1167,12 +1167,7 @@ public slots:
         exp = fixCppExpression(exp);
         if (exp.isEmpty())
             return;
-        const QString name = exp;
-        // Prefer to watch an existing local variable by its expression (address) if it can be found.
-        WatchHandler *watchHandler = currentEngine()->watchHandler();
-        if (const WatchData *localVariable = watchHandler->findCppLocalVariable(exp))
-            exp = QLatin1String(localVariable->exp);
-        watchHandler->watchExpression(exp, name);
+        currentEngine()->watchHandler()->watchVariable(exp);
     }
 
     void handleExecExit()

src/plugins/debugger/watchhandler.cpp

@@ -1586,6 +1586,18 @@ void WatchHandler::watchExpression(const QString &exp, const QString &name)
     updateWatchersWindow();
 }
 
+// Watch something obtained from the editor.
+// Prefer to watch an existing local variable by its expression
+// (address) if it can be found. Default to watchExpression().
+void WatchHandler::watchVariable(const QString &exp)
+{
+    if (const WatchData *localVariable = findCppLocalVariable(exp)) {
+        watchExpression(QLatin1String(localVariable->exp), exp);
+    } else {
+        watchExpression(exp);
+    }
+}
+
 static void swapEndian(char *d, int nchar)
 {
     QTC_ASSERT(nchar % 4 == 0, return);

src/plugins/debugger/watchhandler.h

@@ -77,6 +77,7 @@ public:
 
     void cleanup();
     void watchExpression(const QString &exp, const QString &name = QString());
+    void watchVariable(const QString &exp);
     Q_SLOT void clearWatches();
 
     void updateWatchers(); // Called after locals are fetched

src/plugins/debugger/watchwindow.cpp

@@ -553,7 +553,7 @@ void WatchTreeView::dropEvent(QDropEvent *ev)
         QString data = ev->mimeData()->text();
         foreach (const QChar c, data)
             exp.append(c.isPrint() ? c : QChar(QLatin1Char(' ')));
-        watchExpression(exp);
+        currentEngine()->watchHandler()->watchVariable(exp);
         //ev->acceptProposedAction();
         ev->setDropAction(Qt::CopyAction);
         ev->accept();