Fix broken debugging on Android 5.0

Security permissions prevent access to files not owned by the current
process. This patch replaces the file based handshake protocol with
a local server based implementation. The server waits for QTC to connect
to it and sends back the current process ID. This new mechanism works
on pre 5.0 devices as well.

The existing file based handshake remains and can be activiated via the
env variable QTC_ANDROID_USE_FILE_HANDSHAKE.

Task-number: QTCREATORBUG-13418
Change-Id: Ie40ec801f265a9e13c3220f300798c27abd97ae2
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>
Reviewed-by: hjk <hjk121@nokiamail.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
Reviewed-by: BogDan Vatra <bogdan@kde.org>

src/plugins/android/androidrunner.h

@@ -37,6 +37,7 @@
 
 #include <QObject>
 #include <QTimer>
+#include <QTcpSocket>
 #include <QThread>
 #include <QProcess>
 #include <QMutex>
@@ -50,6 +51,11 @@ class AndroidRunner : public QThread
 {
     Q_OBJECT
 
+    enum DebugHandShakeType {
+        PingPongFiles,
+        SocketHandShake
+    };
+
 public:
     AndroidRunner(QObject *parent, AndroidRunConfiguration *runConfig,
                   ProjectExplorer::RunMode runMode);
@@ -114,6 +120,9 @@ private:
     bool m_isBusyBox;
     QStringList m_selector;
     QMutex m_mutex;
+    DebugHandShakeType m_handShakeMethod;
+    QTcpSocket *m_socket;
+    bool m_customPort;
 };
 
 } // namespace Internal