Hook up the keybindings to the SUI, redux (#10121)

## Summary of the Pull Request

This is a redux of #8882.

From the original:

>  This is really similar to what we're doing with the `CommandPalette`. We're adding a ~~Preview~~`KeyDown` handler to the SUI `MainPage`, that connects to `TerminalPage::_HandleKey`. That allows the SUI a chance to search the keymap to dispatch actions for keybindings, similar to how the command palette does it.
>
> This also means it's now possible for the SUI to invoke _all_ the actions available to the Terminal. This includes the ones like `IncreaseFontSize`, which require a _Terminal_ to actually do something. So we have to make sure all the calls to `_GetActiveControl` actually check that the result is non-null before using it.
>
> A bunch of the actions do nothing now from a SUI tab, others behave _weird_. Like "Rename tab" / "Open Tab Renamer" do nothing. "Duplicate Tab" again does nothing - we try making a new settings tab, which just focuses the settings tab again. "Copy text" definitely does nothing, same with paste.

I don't know why I thought this wouldn't work. I thought we'd have to do this in `PreviewKeyDown` or something, which led to [weirdness](#8882 (comment)). Turns out, we don't need it to be in `PreviewKeyDown`. It can just be in the SUI's `KeyDown`.

## References
* Original: #8882
* Workaround was in #8885

## PR Checklist
* [x] Closes #8767
* [x] I work here
* [x] Tests added/passed
* [n/a] Requires documentation to be updated

## Detailed Description of the Pull Request / Additional comments

The special case handler from #8885 is no longer needed

## Validation Steps Performed

* Switching tabs with Ctrl+Tab works
* Command palette works
* fullscreen, focus mode works
* close window works
* copy paste on Ctrl+C/V works, even when bound
* Select all text in textboxes works
* tab navigation through UI elements works

(cherry picked from commit 52560ff)

# Conflicts:
#	src/cascadia/TerminalApp/TerminalPage.cpp
#	src/cascadia/TerminalApp/TerminalPage.h

src/cascadia/TerminalApp/AppActionHandlers.cpp

@@ -117,9 +117,11 @@ namespace winrt::TerminalApp::implementation
         }
         else if (const auto& realArgs = args.ActionArgs().try_as<SendInputArgs>())
         {
-            const auto termControl = _GetActiveControl();
-            termControl.SendInput(realArgs.Input());
-            args.Handled(true);
+            if (const auto termControl{ _GetActiveControl() })
+            {
+                termControl.SendInput(realArgs.Input());
+                args.Handled(true);
+            }
         }
     }
 
@@ -308,9 +310,11 @@ namespace winrt::TerminalApp::implementation
     {
         if (const auto& realArgs = args.ActionArgs().try_as<AdjustFontSizeArgs>())
         {
-            const auto termControl = _GetActiveControl();
-            termControl.AdjustFontSize(realArgs.Delta());
-            args.Handled(true);
+            if (const auto& termControl{ _GetActiveControl() })
+            {
+                termControl.AdjustFontSize(realArgs.Delta());
+                args.Handled(true);
+            }
         }
     }
 
@@ -324,17 +328,21 @@ namespace winrt::TerminalApp::implementation
     void TerminalPage::_HandleResetFontSize(const IInspectable& /*sender*/,
                                             const ActionEventArgs& args)
     {
-        const auto termControl = _GetActiveControl();
-        termControl.ResetFontSize();
-        args.Handled(true);
+        if (const auto& termControl{ _GetActiveControl() })
+        {
+            termControl.ResetFontSize();
+            args.Handled(true);
+        }
     }
 
     void TerminalPage::_HandleToggleShaderEffects(const IInspectable& /*sender*/,
                                                   const ActionEventArgs& args)
     {
-        const auto termControl = _GetActiveControl();
-        termControl.ToggleShaderEffects();
-        args.Handled(true);
+        if (const auto& termControl{ _GetActiveControl() })
+        {
+            termControl.ToggleShaderEffects();
+            args.Handled(true);
+        }
     }
 
     void TerminalPage::_HandleToggleFocusMode(const IInspectable& /*sender*/,

src/cascadia/TerminalApp/TerminalPage.cpp

@@ -902,30 +902,6 @@ namespace winrt::TerminalApp::implementation
         }
     }
 
-    // Method Description:
-    // Handles preview key on the SUI tab, by handling close tab / next tab / previous tab
-    // This is a temporary solution - we need to fix all key-bindings work from SUI as long as they don't harm
-    // the SUI behavior
-    // Arguments:
-    // - e: the KeyRoutedEventArgs containing info about the keystroke.
-    // Return Value:
-    // - <none>
-    void TerminalPage::_SUIPreviewKeyDownHandler(Windows::Foundation::IInspectable const& /*sender*/, Windows::UI::Xaml::Input::KeyRoutedEventArgs const& e)
-    {
-        auto key = e.OriginalKey();
-        auto const ctrlDown = WI_IsFlagSet(CoreWindow::GetForCurrentThread().GetKeyState(winrt::Windows::System::VirtualKey::Control), CoreVirtualKeyStates::Down);
-        auto const altDown = WI_IsFlagSet(CoreWindow::GetForCurrentThread().GetKeyState(winrt::Windows::System::VirtualKey::Menu), CoreVirtualKeyStates::Down);
-        auto const shiftDown = WI_IsFlagSet(CoreWindow::GetForCurrentThread().GetKeyState(winrt::Windows::System::VirtualKey::Shift), CoreVirtualKeyStates::Down);
-
-        winrt::Microsoft::Terminal::Control::KeyChord kc{ ctrlDown, altDown, shiftDown, static_cast<int32_t>(key) };
-        const auto actionAndArgs = _settings.KeyMap().TryLookup(kc);
-        if (actionAndArgs && (actionAndArgs.Action() == ShortcutAction::CloseTab || actionAndArgs.Action() == ShortcutAction::NextTab || actionAndArgs.Action() == ShortcutAction::PrevTab || actionAndArgs.Action() == ShortcutAction::ClosePane))
-        {
-            _actionDispatch->DoAction(actionAndArgs);
-            e.Handled(true);
-        }
-    }
-
     // Method Description:
     // - Configure the AppKeyBindings to use our ShortcutActionDispatch and the updated KeyMapping
     // as the object to handle dispatching ShortcutAction events.
@@ -1290,10 +1266,12 @@ namespace winrt::TerminalApp::implementation
         // Do nothing if for some reason, there's no terminal tab in focus. We don't want to crash.
         if (const auto terminalTab{ _GetFocusedTabImpl() })
         {
-            const auto control = _GetActiveControl();
-            const auto termHeight = control.GetViewHeight();
-            auto scrollDelta = _ComputeScrollDelta(scrollDirection, termHeight);
-            terminalTab->Scroll(scrollDelta);
+            if (const auto& control{ _GetActiveControl() })
+            {
+                const auto termHeight = control.ViewHeight();
+                auto scrollDelta = _ComputeScrollDelta(scrollDirection, termHeight);
+                terminalTab->Scroll(scrollDelta);
+            }
         }
     }
 
@@ -1689,8 +1667,11 @@ namespace winrt::TerminalApp::implementation
     // - true iff we we able to copy text (if a selection was active)
     bool TerminalPage::_CopyText(const bool singleLine, const Windows::Foundation::IReference<CopyFormat>& formats)
     {
-        const auto control = _GetActiveControl();
-        return control.CopySelectionToClipboard(singleLine, formats);
+        if (const auto& control{ _GetActiveControl() })
+        {
+            return control.CopySelectionToClipboard(singleLine, formats);
+        }
+        return false;
     }
 
     // Method Description:
@@ -1707,8 +1688,10 @@ namespace winrt::TerminalApp::implementation
     // - Paste text from the Windows Clipboard to the focused terminal
     void TerminalPage::_PasteText()
     {
-        const auto control = _GetActiveControl();
-        control.PasteTextFromClipboard();
+        if (const auto& control{ _GetActiveControl() })
+        {
+            control.PasteTextFromClipboard();
+        }
     }
 
     // Function Description:
@@ -2042,8 +2025,10 @@ namespace winrt::TerminalApp::implementation
     // - <none>
     void TerminalPage::_Find()
     {
-        const auto termControl = _GetActiveControl();
-        termControl.CreateSearchBoxControl();
+        if (const auto& control{ _GetActiveControl() })
+        {
+            control.CreateSearchBoxControl();
+        }
     }
 
     // Method Description:
@@ -2312,7 +2297,8 @@ namespace winrt::TerminalApp::implementation
                 sui.SetHostingWindow(reinterpret_cast<uint64_t>(*_hostingHwnd));
             }
 
-            sui.PreviewKeyDown({ this, &TerminalPage::_SUIPreviewKeyDownHandler });
+            // GH#8767 - let unhandled keys in the SUI try to run commands too.
+            sui.KeyDown({ this, &TerminalPage::_KeyDownHandler });
 
             sui.OpenJson([weakThis{ get_weak() }](auto&& /*s*/, winrt::Microsoft::Terminal::Settings::Model::SettingsTarget e) {
                 if (auto page{ weakThis.get() })

src/cascadia/TerminalApp/TerminalPage.h

@@ -197,7 +197,6 @@ namespace winrt::TerminalApp::implementation
         void _ThirdPartyNoticesOnClick(const IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& eventArgs);
 
         void _KeyDownHandler(Windows::Foundation::IInspectable const& sender, Windows::UI::Xaml::Input::KeyRoutedEventArgs const& e);
-        void _SUIPreviewKeyDownHandler(Windows::Foundation::IInspectable const& sender, Windows::UI::Xaml::Input::KeyRoutedEventArgs const& e);
         void _HookupKeyBindings(const Microsoft::Terminal::Settings::Model::KeyMapping& keymap) noexcept;
         void _RegisterActionCallbacks();