Android: Optimize isConnected()

Before, the implementation used connectedDevices() function
which constructs the detailed info about each device
found, including running 3 extra processes for each device
in a loop. For the purpose of isConnected() - the detailed
info isn't really necessary - it's enough to parse the output
of the {adbToolPath(), {"devices"}} command and detect if
the requested serialNumber appears there. We skip executing
3 additional processes for each device found.

Change-Id: I34f79fb56b4aa4d52a284bc2c67ae01a3467b505
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/android/androidconfigurations.cpp

@@ -731,9 +731,18 @@ QList<AndroidDeviceInfo> connectedDevices(QString *error)
 
 bool isConnected(const QString &serialNumber)
 {
-    const QList<AndroidDeviceInfo> devices = connectedDevices();
-    for (const AndroidDeviceInfo &device : devices) {
-        if (device.serialNumber == serialNumber)
+    Process adbProcess;
+    adbProcess.setCommand({adbToolPath(), {"devices"}});
+    adbProcess.runBlocking();
+    if (adbProcess.result() != ProcessResult::FinishedWithSuccess)
+        return false;
+
+    // mid(1) - remove "List of devices attached" header line.
+    // Example output: "List of devices attached\nemulator-5554\tdevice\n\n".
+    const QStringList lines = adbProcess.allOutput().split('\n', Qt::SkipEmptyParts).mid(1);
+    for (const QString &line : lines) {
+        // skip the daemon logs
+        if (!line.startsWith("* daemon") && line.left(line.indexOf('\t')).trimmed() == serialNumber)
             return true;
     }
     return false;