Android: null pointer check

Task-number: QTBUG-41680
Change-Id: I740fb2a6df5613a8ee724b59dab08674a3337236
Reviewed-by: Kai Uwe Broulik <kde@privat.broulik.de>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
Android: Thread fix/optimization

Do the cheap test before sending an expensive query that might
use a mutex.

Task-number: QTBUG-41369
Change-Id: I78f03c84e5bbf0492f1b7ea18d1baa752a1beff2
Reviewed-by: Christian Stromme <christian.stromme@digia.com>
Android: Support QClipboard::clear()

QClipboard::clear() is implemented by calling
QPlatformClipboard::setMimeData() with a null pointer. Since we
would do nothing in this case on Android, then the clear()
function would have no effect.

[ChangeLog][Android] Added support for QClipboard::clear()

Task-number: QTBUG-41854
Change-Id: Id569b102f2e561e46967b52f89d9b54031d92456
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Android: Fix memory leak in QClipboard::setMimeData()

The ownership of the object passed into QClipboard::setMimeData()
is documented to be transferred to the clipboard, but we never
deleted it, thus all these objects would leak.

[ChangeLog][Android] Fixed memory leak in QClipboard::setMimeData()

Change-Id: I43e6bad1071be5f56c219cb9341584edba54d2bd
Task-number: QTBUG-41852
Reviewed-by: BogDan Vatra <bogdan@kde.org>
Prevent parsing of SSL certificates from 0-size buffers.

When QSslCertificatePrivate::certificatesFromDer() was passed count ==
-1 to extract unlimied number of certificates from buffer, it also tried
to parse the 0-sized fragment after the last certificate.  This has
caused d2i_X509() to report an error on latest OpenSSL.

Task-number: QTBUG-41774
Change-Id: Ifa36b7ac5b4236bd2fb53b9d7fe53c5db3cb078c
Reviewed-by: Peter Hartmann <phartmann@blackberry.com>
Add information about unsupported SSL protocol when creating context.

When creating SSL context failed due to unsupported protocol being
demanded, no explanation was given. It's because
QSslContext::fromConfiguration() extracted explanation for error message
from OpenSSL, which at that point hasn't even been called yet. This
patch adds explicit message informing that an unsupported protocol was
chosen.

Task-number: QTBUG-41775
Change-Id: I9d2710da4ba314a16837a90afcdc5d9256179bef
Reviewed-by: Peter Hartmann <phartmann@blackberry.com>