wasm: set focus to m_canvas instead of m_window

Setting focus and contentEditable on m_window causes
innerHTML to build up with characters.

This does not happen when using the m_canvas

The downside is that m_canvas is aria-hidden, but this
should, in principle, not be a problem since
m_canvas should not be focused when a11y is in
effect.

Later aria-hidden might be set only if a11y is in
effect.

It turns out this also fixes tabbing between textfields
and buttons bug.

This is a candidate for manual cherry-picking to
6.9 6.9.1

Task-number: QTBUG-136687
Task-number: QTBUG-136562
Change-Id: I08a9db2c39f9b0b0038c75fd06d3504b736ea031
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

src/plugins/platforms/wasm/qwasmclipboard.cpp

@@ -86,26 +86,10 @@ void QWasmClipboard::paste(val event)
     QWasmIntegration::get()->getWasmClipboard()->sendClipboardData(event);
 }
 
-void QWasmClipboard::beforeInput(emscripten::val event)
-{
-    event.call<void>("preventDefault");
-    event.call<void>("stopPropagation");
-}
-
-void QWasmClipboard::input(emscripten::val event)
-{
-    event.call<void>("preventDefault");
-    event.call<void>("stopPropagation");
-    event["target"].set("innerHTML", std::string());
-    event["target"].set("value", std::string());
-}
-
 EMSCRIPTEN_BINDINGS(qtClipboardModule) {
     function("qtClipboardCutTo", &QWasmClipboard::cut);
     function("qtClipboardCopyTo", &QWasmClipboard::copy);
     function("qtClipboardPasteTo", &QWasmClipboard::paste);
-    function("qtClipboardBeforeInput", &QWasmClipboard::beforeInput);
-    function("qtClipboardInput", &QWasmClipboard::input);
 }
 
 QWasmClipboard::QWasmClipboard()

src/plugins/platforms/wasm/qwasmclipboard.h

@@ -43,8 +43,6 @@ public:
     static void cut(emscripten::val event);
     static void copy(emscripten::val event);
     static void paste(emscripten::val event);
-    static void beforeInput(emscripten::val event);
-    static void input(emscripten::val event);
 
 private:
     void initClipboardPermissions();

src/plugins/platforms/wasm/qwasmwindow.cpp

@@ -56,7 +56,6 @@ QWasmWindow::QWasmWindow(QWindow *w, QWasmDeadKeySupport *deadKeySupport,
       m_document(dom::document()),
       m_decoratedWindow(m_document.call<emscripten::val>("createElement", emscripten::val("div"))),
       m_window(m_document.call<emscripten::val>("createElement", emscripten::val("div"))),
-      m_windowInput(m_document.call<emscripten::val>("createElement", emscripten::val("div"))),
       m_a11yContainer(m_document.call<emscripten::val>("createElement", emscripten::val("div"))),
       m_canvas(m_document.call<emscripten::val>("createElement", emscripten::val("canvas")))
 {
@@ -71,17 +70,26 @@ QWasmWindow::QWasmWindow(QWindow *w, QWasmDeadKeySupport *deadKeySupport,
     m_window.set("className", "qt-window");
     m_decoratedWindow.call<void>("appendChild", m_window);
 
-    m_window.call<void>("appendChild", m_windowInput);
     m_canvas["classList"].call<void>("add", emscripten::val("qt-window-canvas"));
 
+    // Set contentEditable for two reasons;
+    //   1) so that the window gets clipboard events,
+    //   2) For applications who will handle keyboard events, but without having inputMethodAccepted()
+    //
+    // Set inputMode to none to avoid keyboard popping up on push buttons
+    // This is a tradeoff, we are not able to separate between a push button and
+    // a widget that reads keyboard events.
+    m_canvas.call<void>("setAttribute", std::string("inputmode"), std::string("none"));
+    m_canvas.call<void>("setAttribute", std::string("contenteditable"), std::string("true"));
+    m_canvas["style"].set("outline", std::string("none"));
+
 #if QT_CONFIG(clipboard)
-    QWasmClipboard::installEventHandlers(m_windowInput);
+    QWasmClipboard::installEventHandlers(m_canvas);
 #endif
 
     // Set inputMode to none to stop the mobile keyboard from opening
     // when the user clicks on the window.
     m_window.set("inputMode", std::string("none"));
-    m_windowInput.set("inputMode", std::string("none"));
 
     // Hide the canvas from screen readers.
     m_canvas.call<void>("setAttribute", std::string("aria-hidden"), std::string("true"));
@@ -119,9 +127,9 @@ QWasmWindow::QWasmWindow(QWindow *w, QWasmDeadKeySupport *deadKeySupport,
             [this](emscripten::val event) { this->handleKeyForInputContextEvent(event); });
     }
 
-    m_keyDownCallback = std::make_unique<qstdweb::EventCallback>(m_window, "keydown",
+    m_keyDownCallback = std::make_unique<qstdweb::EventCallback>(m_canvas, "keydown",
         [this](emscripten::val event) { this->handleKeyEvent(event); });
-    m_keyUpCallback =std::make_unique<qstdweb::EventCallback>(m_window, "keyup",
+    m_keyUpCallback =std::make_unique<qstdweb::EventCallback>(m_canvas, "keyup",
         [this](emscripten::val event) { this->handleKeyEvent(event); });
 
     setParent(parent());
@@ -718,7 +726,7 @@ void QWasmWindow::requestActivateWindow()
 
 void QWasmWindow::focus()
 {
-    m_windowInput.call<void>("focus");
+    m_canvas.call<void>("focus");
 }
 
 bool QWasmWindow::setMouseGrabEnabled(bool grab)

src/plugins/platforms/wasm/qwasmwindow.h

@@ -140,7 +140,6 @@ private:
     emscripten::val m_document;
     emscripten::val m_decoratedWindow;
     emscripten::val m_window;
-    emscripten::val m_windowInput;
     emscripten::val m_a11yContainer;
     emscripten::val m_canvas;
     emscripten::val m_context2d = emscripten::val::undefined();