Implement keyboard access between bookmarks and toolbar.

chrome/browser/views/accessible_toolbar_view.cc

+// Copyright (c) 2009 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 "base/logging.h"
+#include "chrome/browser/view_ids.h"
+#include "chrome/browser/views/frame/browser_view.h"
+#include "chrome/browser/views/accessible_toolbar_view.h"
+#include "views/controls/button/menu_button.h"
+#include "views/focus/view_storage.h"
+#include "views/widget/tooltip_manager.h"
+#include "views/widget/widget.h"
+
+AccessibleToolbarView::AccessibleToolbarView()
+    : selected_focused_view_(NULL),
+      last_focused_view_storage_id_(-1) {
+}
+
+AccessibleToolbarView::~AccessibleToolbarView() {
+}
+
+void AccessibleToolbarView::InitiateTraversal(int view_storage_id) {
+  // We only traverse if accessibility is active.
+  if (selected_focused_view_)
+    return;
+
+  // Save the storage id to the last focused view. This would be used to request
+  // focus to the view when the traversal is ended.
+  last_focused_view_storage_id_ = view_storage_id;
+
+  // Request focus to the toolbar.
+  RequestFocus();
+}
+
+views::View* AccessibleToolbarView::GetNextAccessibleView(int view_index,
+                                                          bool forward) {
+  int modifier = forward ? 1 : -1;
+  int current_view_index = view_index + modifier;
+
+  while ((current_view_index >= 0) &&
+         (current_view_index < GetChildViewCount())) {
+    // Try to find the next available view that can be interacted with. That
+    // view must be enabled, visible, and traversable.
+    views::View* current_view = GetChildViewAt(current_view_index);
+    if (current_view->IsEnabled() && current_view->IsVisible() &&
+        IsAccessibleViewTraversable(current_view)) {
+      return current_view;
+    }
+    current_view_index += modifier;
+  }
+
+  // No button is available in the specified direction.
+  return NULL;
+}
+
+bool AccessibleToolbarView::IsAccessibleViewTraversable(views::View* view) {
+  return true;
+}
+
+void AccessibleToolbarView::DidGainFocus() {
+  // Check to see if the accessible focus should be restored to previously
+  // focused button. The must be enabled and visible in the toolbar.
+  if (!selected_focused_view_ ||
+      !selected_focused_view_->IsEnabled() ||
+      !selected_focused_view_->IsVisible()) {
+    // Find first accessible child (-1 to start search at parent).
+    selected_focused_view_ = GetNextAccessibleView(-1, true);
+
+    // No buttons enabled or visible.
+    if (!selected_focused_view_)
+      return;
+  }
+
+  // Set the focus to the current accessible view.
+  SetFocusToAccessibleView();
+}
+
+void AccessibleToolbarView::WillLoseFocus() {
+  // Any tooltips that are active should be hidden when toolbar loses focus.
+  if (GetWidget() && GetWidget()->GetTooltipManager())
+    GetWidget()->GetTooltipManager()->HideKeyboardTooltip();
+
+  // Removes the child accessibility view's focus when toolbar loses focus. It
+  // will not remove the view from the ViewStorage because it might be
+  // traversing to another toolbar hence the last focused view should not be
+  // removed.
+  if (selected_focused_view_) {
+    selected_focused_view_->SetHotTracked(false);
+    selected_focused_view_ = NULL;
+  }
+}
+
+void AccessibleToolbarView::ShowContextMenu(int x, int y,
+                                            bool is_mouse_gesture) {
+  if (selected_focused_view_)
+    selected_focused_view_->ShowContextMenu(x, y, is_mouse_gesture);
+}
+
+void AccessibleToolbarView::RequestFocus() {
+  // When the toolbar needs to request focus, the default implementation of
+  // View::RequestFocus requires the View to be focusable. Since ToolbarView is
+  // not technically focused, we need to temporarily set and remove focus so
+  // that it can focus back to its focused state. |selected_focused_view_| is
+  // not necessarily set since it can be null if this view has already lost
+  // focus, such as traversing through the context menu.
+  SetFocusable(true);
+  View::RequestFocus();
+  SetFocusable(false);
+}
+
+bool AccessibleToolbarView::OnKeyPressed(const views::KeyEvent& e) {
+  if (!HasFocus())
+    return View::OnKeyPressed(e);
+
+  int focused_view = GetChildIndex(selected_focused_view_);
+  views::View* next_view = NULL;
+
+  switch (e.GetKeyCode()) {
+    case base::VKEY_LEFT:
+      next_view = GetNextAccessibleView(focused_view, false);
+      break;
+    case base::VKEY_RIGHT:
+      next_view = GetNextAccessibleView(focused_view, true);
+      break;
+    case base::VKEY_DOWN:
+    case base::VKEY_RETURN:
+      if (selected_focused_view_ && selected_focused_view_->GetClassName() ==
+          views::MenuButton::kViewClassName) {
+        // If a menu button is activated and its menu is displayed, then the
+        // active tooltip should be hidden.
+        if (GetWidget()->GetTooltipManager())
+          GetWidget()->GetTooltipManager()->HideKeyboardTooltip();
+
+        // Safe to cast, given to above check.
+        static_cast<views::MenuButton*>(selected_focused_view_)->Activate();
+
+        // If activate did not trigger a focus change, the menu button should
+        // remain hot tracked since the view is still focused.
+        if (selected_focused_view_)
+          selected_focused_view_->SetHotTracked(true);
+        return true;
+      }
+    default:
+      // If key is not handled explicitly, pass it on to view.
+      if (selected_focused_view_)
+        return selected_focused_view_->OnKeyPressed(e);
+      else
+        return View::OnKeyPressed(e);
+  }
+
+  // No buttons enabled, visible, or focus hasn't moved.
+  if (next_view == NULL || !selected_focused_view_)
+    return false;
+
+  // Remove hot-tracking from old focused button.
+  selected_focused_view_->SetHotTracked(false);
+
+  // All is well, update the focused child member variable.
+  selected_focused_view_ = next_view;
+
+  // Set the focus to the current accessible view.
+  SetFocusToAccessibleView();
+  return true;
+}
+
+bool AccessibleToolbarView::OnKeyReleased(const views::KeyEvent& e) {
+  if (!selected_focused_view_)
+    return false;
+
+  // Have keys be handled by the views themselves.
+  return selected_focused_view_->OnKeyReleased(e);
+}
+
+bool AccessibleToolbarView::SkipDefaultKeyEventProcessing(
+    const views::KeyEvent& e) {
+  // Accessibility focus must be present in order to handle ESC and TAB related
+  // key events.
+  if (!HasFocus())
+    return false;
+
+  // The ancestor *must* be a BrowserView.
+  views::View* view = GetAncestorWithClassName(BrowserView::kViewClassName);
+  if (!view)
+    return false;
+
+  // Given the check above, we can ensure its a BrowserView.
+  BrowserView* browser_view = static_cast<BrowserView*>(view);
+
+  // Handle ESC and TAB events.
+  switch (e.GetKeyCode()) {
+    case base::VKEY_ESCAPE: {
+      SetFocusToLastFocusedView();
+      return true;
+    }
+    case base::VKEY_TAB: {
+      if (e.IsShiftDown()) {
+        browser_view->TraverseNextAccessibleToolbar(false);
+      } else {
+        browser_view->TraverseNextAccessibleToolbar(true);
+      }
+      return true;
+    }
+    default: return false;
+  }
+}
+
+bool AccessibleToolbarView::GetAccessibleName(std::wstring* name) {
+  *name = accessible_name_;
+  return !accessible_name_.empty();
+}
+
+bool AccessibleToolbarView::GetAccessibleRole(AccessibilityTypes::Role* role) {
+  DCHECK(role);
+
+  *role = AccessibilityTypes::ROLE_TOOLBAR;
+  return true;
+}
+
+void AccessibleToolbarView::SetAccessibleName(const std::wstring& name) {
+  accessible_name_ = name;
+}
+
+void AccessibleToolbarView::ViewHierarchyChanged(bool is_add, View* parent,
+                                                 View* child) {
+  // When the toolbar is removed, traverse to the next accessible toolbar.
+  if (child == selected_focused_view_ && !is_add) {
+    selected_focused_view_->SetHotTracked(false);
+    selected_focused_view_ = NULL;
+    SetFocusToLastFocusedView();
+  }
+}
+
+void AccessibleToolbarView::SetFocusToAccessibleView() {
+  // Hot-track new focused button.
+  selected_focused_view_->SetHotTracked(true);
+
+  // Show the tooltip for the view that got the focus.
+  if (GetWidget()->GetTooltipManager()) {
+    GetWidget()->GetTooltipManager()->ShowKeyboardTooltip(
+        selected_focused_view_);
+  }
+
+#if defined(OS_WIN)
+  // Retrieve information to generate an accessible focus event.
+  gfx::NativeView wnd = GetWidget()->GetNativeView();
+  int view_id = selected_focused_view_->GetID();
+  // Notify Access Technology that there was a change in keyboard focus.
+  ::NotifyWinEvent(EVENT_OBJECT_FOCUS, wnd, OBJID_CLIENT,
+                   static_cast<LONG>(view_id));
+#else
+  NOTIMPLEMENTED();
+#endif
+}
+
+void AccessibleToolbarView::SetFocusToLastFocusedView() {
+    views::ViewStorage* view_storage = views::ViewStorage::GetSharedInstance();
+    views::View* focused_view =
+        view_storage->RetrieveView(last_focused_view_storage_id_);
+    if (focused_view) {
+      view_storage->RemoveView(last_focused_view_storage_id_);
+      focused_view->RequestFocus();
+    } else {
+      // The ancestor *must* be a BrowserView. The check below can ensure that.
+      views::View* view = GetAncestorWithClassName(BrowserView::kViewClassName);
+      if (!view)
+        return;
+      BrowserView* browser_view = static_cast<BrowserView*>(view);
+
+      // Force the focus to be set on the location bar.
+      browser_view->SetFocusToLocationBar();
+    }
+}