Harmonize input context selection

Input context selection works differently across platforms. On some
platforms it is not possible to request a specific context at all
(e.g. Wayland). This will be unified, depending on the environment
variable "QT_IM_MODULE", you will get:
- null:  default (platform) context, if defined (otherwise no context)
- empty: no context
- set:   set one, if it exists and is valid (otherwise no context)

[ChangeLog][Platform Specific Changes] Haromnized input context selection.
QT_IM_MODULE environment variable will be taken into account.

Change-Id: Ic8f826fbc6ace25941cd19b9b086943e848fbe01
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
Reviewed-by: Nedim Hadzic <nedim.hadzic@pelagicore.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/gui/kernel/qplatforminputcontextfactory_p.h b/src/gui/kernel/qplatforminputcontextfactory_p.h
index a74c4f5f80..38f4358287 100644
--- a/src/gui/kernel/qplatforminputcontextfactory_p.h
+++ b/src/gui/kernel/qplatforminputcontextfactory_p.h
@@ -56,6 +56,7 @@ class Q_GUI_EXPORT QPlatformInputContextFactory
 {
 public:
     static QStringList keys();
+    static QString requested();
     static QPlatformInputContext *create(const QString &key);
     static QPlatformInputContext *create();
 };