PerfProfiler: Delay closing of perfparser's write channel

We don't want to do this from writeChunk() as that is directly connected
to QProcess::bytesWritten. closeWriteChannel() can delete the
QWindowsPipeWriter from which the bytesWritten signal originates, crashing
the event loop when it tries to resolve further receivers for the same
signal.

Change-Id: I66737572a33db364f0f61542343f0fc8dc696787
Task-number: QTCREATORBUG-21971
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/perfprofiler/perfdatareader.cpp

@@ -351,8 +351,10 @@ void PerfDataReader::writeChunk()
                                         "Your trace is incomplete."));
             }
         }
-    } else if (m_dataFinished) {
-        m_input.closeWriteChannel();
+    } else if (m_dataFinished && m_input.isWritable()) {
+        // Delay closing of the write channel. Closing the channel from within a handler
+        // for bytesWritten() is dangerous on windows.
+        QTimer::singleShot(0, &m_input, &QProcess::closeWriteChannel);
     }
 }