citra_qt/applets/swkbd: QtKeyboard and misc fixes

* Addressed comments and removed the applet interface

* swkbd: address @lioncash's comments

* core: more fixes

** Moved registered_swkbd to System

** Removed an usused virtual

** Removed functionality of DrawScreenKeyboard

** Removed src/core/settings.h change

* swkbd: address @lioncash's 2nd review

* swkbd: update logging macro

* QtKeyboard: Make dialog modal and hide help

src/citra_qt/applets/swkbd.h

@@ -0,0 +1,65 @@
+// Copyright 2018 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <QDialog>
+#include <QValidator>
+#include "core/frontend/applets/swkbd.h"
+
+class QDialogButtonBox;
+class QLabel;
+class QLineEdit;
+class QVBoxLayout;
+class QtKeyboard;
+
+class QtKeyboardValidator final : public QValidator {
+public:
+    explicit QtKeyboardValidator(QtKeyboard* keyboard);
+    State validate(QString& input, int& pos) const override;
+
+private:
+    QtKeyboard* keyboard;
+};
+
+class QtKeyboardDialog final : public QDialog {
+    Q_OBJECT
+
+public:
+    QtKeyboardDialog(QWidget* parent, QtKeyboard* keyboard);
+    void Submit();
+
+private:
+    void HandleValidationError(Frontend::ValidationError error);
+    QDialogButtonBox* buttons;
+    QLabel* label;
+    QLineEdit* line_edit;
+    QVBoxLayout* layout;
+    QtKeyboard* keyboard;
+    QString text;
+    u8 button;
+
+    friend class QtKeyboard;
+};
+
+class QtKeyboard final : public QObject, public Frontend::SoftwareKeyboard {
+    Q_OBJECT
+
+public:
+    explicit QtKeyboard(QWidget& parent);
+    void Setup(const Frontend::KeyboardConfig* config) override;
+
+private:
+    Q_INVOKABLE void OpenInputDialog();
+
+    /// Index of the buttons
+    u8 ok_id;
+    static constexpr u8 forgot_id = 1;
+    static constexpr u8 cancel_id = 0;
+
+    QWidget& parent;
+
+    friend class QtKeyboardDialog;
+    friend class QtKeyboardValidator;
+};