Revert "Change minimum Qt version to 5.10"

This reverts commit 19cce0c838.

CMakeLists.txt

@@ -44,7 +44,7 @@ endif()
 add_definitions(-DQT_NO_URL_CAST_FROM_STRING -DQT_USE_QSTRINGBUILDER -DQT_NO_CAST_TO_ASCII)
 
 # Mandatory: Qt5
-set(QT_MIN_VERSION "5.10.0")
+set(QT_MIN_VERSION "5.9.0")
 find_package(Qt5 ${QT_MIN_VERSION} REQUIRED COMPONENTS Core Widgets Network Sql QuickWidgets PrintSupport WebEngine WebEngineWidgets WebChannel)
 if (BUILD_TESTING)
     find_package(Qt5 ${QT_MIN_VERSION} REQUIRED COMPONENTS Test)

src/lib/app/mainapplication.cpp

@@ -929,7 +929,10 @@ void MainApplication::loadSettings()
     webSettings->setAttribute(QWebEngineSettings::FullScreenSupportEnabled, true);
     webSettings->setAttribute(QWebEngineSettings::LocalContentCanAccessRemoteUrls, true);
     webSettings->setAttribute(QWebEngineSettings::FocusOnNavigationEnabled, false);
+
+#if QTWEBENGINEWIDGETS_VERSION >= QT_VERSION_CHECK(5, 10, 0)
     webSettings->setAttribute(QWebEngineSettings::AllowWindowActivationFromJavaScript, settings.value(QSL("allowJavaScriptActivateWindow"), false).toBool());
+#endif
 
 #if QTWEBENGINEWIDGETS_VERSION >= QT_VERSION_CHECK(5, 11, 0)
     webSettings->setAttribute(QWebEngineSettings::JavascriptCanPaste, settings.value(QSL("allowJavaScriptPaste"), true).toBool());

src/lib/preferences/jsoptions.cpp

@@ -30,6 +30,10 @@ JsOptions::JsOptions(QWidget* parent)
 
     ui->setupUi(this);
 
+#if QTWEBENGINEWIDGETS_VERSION < QT_VERSION_CHECK(5, 10, 0)
+    ui->jscanActivateWindow->setVisible(false);
+#endif
+
 #if QTWEBENGINEWIDGETS_VERSION < QT_VERSION_CHECK(5, 11, 0)
     ui->jscanPaste->setVisible(false);
 #endif

src/lib/webengine/webview.cpp

@@ -496,6 +496,7 @@ void WebView::copyLinkToClipboard()
 
 void WebView::savePageAs()
 {
+#if QTWEBENGINEWIDGETS_VERSION >= QT_VERSION_CHECK(5, 10, 0)
     page()->runJavaScript(QSL("document.contentType"), WebPage::SafeJsWorld, [this](const QVariant &res) {
         const QSet<QString> webPageTypes = {
             QSL("text/html"),
@@ -507,6 +508,9 @@ void WebView::savePageAs()
             page()->download(url());
         }
     });
+#else
+    triggerPageAction(QWebEnginePage::SavePage);
+#endif
 }
 
 void WebView::copyImageToClipboard()