Enable keyboard accelerators while a menu is open

ui/views/controls/menu/menu_key_event_handler.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/views/controls/menu/menu_key_event_handler.h"
+
+#include "ui/aura/env.h"
+#include "ui/events/keycodes/keyboard_code_conversion.h"
+#include "ui/views/controls/menu/menu_controller.h"
+#include "ui/views/views_delegate.h"
+
+namespace views {
+
+namespace {
+
+const int kKeyFlagsMask = ui::EF_CONTROL_DOWN | ui::EF_ALT_DOWN;
+
+}  // namespace
+
+MenuKeyEventHandler::MenuKeyEventHandler() {
+  aura::Env::GetInstanceDontCreate()->PrependPreTargetHandler(this);
+}
+
+MenuKeyEventHandler::~MenuKeyEventHandler() {
+  aura::Env::GetInstanceDontCreate()->RemovePreTargetHandler(this);
+}
+
+void MenuKeyEventHandler::OnKeyEvent(ui::KeyEvent* event) {
+  MenuController* menu_controller = MenuController::GetActiveInstance();
+  DCHECK(menu_controller);
+
+  if (menu_controller->exit_type() == MenuController::EXIT_ALL ||
+      menu_controller->exit_type() == MenuController::EXIT_DESTROYED) {
+    // If the event has arrived after the menu's exit type had changed but
+    // before its message loop terminated, the event will continue its normal
+    // propagation for the following reason:
+    // If the user accepts a menu item in a nested menu, the menu item action is
+    // run after the base::RunLoop for the innermost menu has quit but before
+    // the base::RunLoop for the outermost menu has quit. If the menu item
+    // action starts a base::RunLoop, the outermost menu's base::RunLoop will
+    // not quit till the action's base::RunLoop ends. IDC_BOOKMARK_BAR_OPEN_ALL
+    // sometimes opens a modal dialog. The modal dialog starts a base::RunLoop
+    // and keeps the base::RunLoop running for the duration of its lifetime.
+    menu_controller->TerminateNestedMessageLoop();
+    return;
+  }
+
+  if (event->type() == ui::ET_KEY_PRESSED) {
+    menu_controller->OnKeyDown(event->key_code());
+
+    // Do not check mnemonics if the Alt or Ctrl modifiers are pressed. For
+    // example Ctrl+<T> is an accelerator, but <T> only is a mnemonic.
+    const int flags = event->flags();
+    if (menu_controller->exit_type() == MenuController::EXIT_NONE &&
+        (flags & kKeyFlagsMask) == 0) {
+      char c = ui::DomCodeToUsLayoutCharacter(event->code(), flags);
+      menu_controller->SelectByChar(c);
+    }
+  }
+
+  if (menu_controller->exit_type() != MenuController::EXIT_NONE) {
+    menu_controller->TerminateNestedMessageLoop();
+  } else {
+    ui::Accelerator accelerator(*event);
+    ViewsDelegate::ProcessMenuAcceleratorResult result =
+        ViewsDelegate::GetInstance()->ProcessAcceleratorWhileMenuShowing(
+            accelerator);
+    if (result == ViewsDelegate::ProcessMenuAcceleratorResult::CLOSE_MENU)
+      menu_controller->CancelAll();
+  }
+
+  event->StopPropagation();
+}
+
+}  // namespace views