MacViews: Implement Full Keyboard Access.

ui/views/focus/focus_manager.cc

Index: ui/views/focus/focus_manager.cc
diff --git a/ui/views/focus/focus_manager.cc b/ui/views/focus/focus_manager.cc
index c84c3152734d2de2994673aee76b89365884d19d..932cae020ac8b7fa3fbf57ecdb57ffa52ba3483e 100644
--- a/ui/views/focus/focus_manager.cc
+++ b/ui/views/focus/focus_manager.cc
@@ -35,7 +35,8 @@ FocusManager::FocusManager(Widget* widget, FocusManagerDelegate* delegate)
       accelerator_manager_(new ui::AcceleratorManager),
       shortcut_handling_suspended_(false),
       focus_change_reason_(kReasonDirectFocusChange),
-      is_changing_focus_(false) {
+      is_changing_focus_(false),
+      keyboard_accessible_(false) {
   DCHECK(widget_);
   stored_focused_view_storage_id_ =
       ViewStorage::GetInstance()->CreateStorageID();
@@ -297,6 +298,16 @@ View* FocusManager::GetNextFocusableView(View* original_starting_view,
   return NULL;
 }
 
+void FocusManager::SetKeyboardAccessible(bool keyboard_accessible) {
+  if (keyboard_accessible == keyboard_accessible_)
+    return;
+
+  keyboard_accessible_ = keyboard_accessible;
+  // Disabling keyboard accessibility may cause the focused view to become not
+  // focusable. Hence advance focus if necessary.
+  AdvanceFocusIfNecessary();
+}
+
 void FocusManager::SetFocusedViewWithReason(
     View* view, FocusChangeReason reason) {
   if (focused_view_ == view)
@@ -341,9 +352,9 @@ void FocusManager::AdvanceFocusIfNecessary() {
 
   // If widget is active and focused view is not focusable, advance focus or,
   // if not possible, clear focus.
-  if (focused_view_ && !focused_view_->IsAccessibilityFocusable()) {
+  if (focused_view_ && !IsFocusable(focused_view_)) {
     AdvanceFocus(false);
-    if (focused_view_ && !focused_view_->IsAccessibilityFocusable())
+    if (focused_view_ && !IsFocusable(focused_view_))
       ClearFocus();
   }
 }
@@ -378,6 +389,7 @@ bool FocusManager::RestoreFocusedView() {
   View* view = GetStoredFocusView();
   if (view) {
     if (ContainsView(view)) {
+      // Todo change this.
       if (!view->IsFocusable() && view->IsAccessibilityFocusable()) {

[karandeepb, 2016/03/15 02:19:51]

I can't understand the rationale behind this line of code. It is introduced here
- https://codereview.chromium.org/3013023. Any insights?

[tapted, 2016/03/15 05:05:31]

So I think `RequestFocus` can be overridden by a View. Before that CL you link
to, the logic here would have bypassed any RequestFocus override, which is bad
[some things rely on that override]. So, where possible, RequstFocus should be
used rather than SetFocusedViewWithReason. 

But since the default implementation of View::RequestFocus checks only
`IsFocusable`, it can't be called for views that are only
`AccessibilityFocusable`, so for that case only, it falls back to calling
SetFocusedView directly.

[karandeepb, 2016/03/17 07:24:46]

Thanks!

         // RequestFocus would fail, but we want to restore focus to controls
         // that had focus in accessibility mode.
@@ -393,9 +405,11 @@ bool FocusManager::RestoreFocusedView() {
           focus_change_reason_ = kReasonFocusRestore;
       }
     }
-    return true;
+    // The |keyboard_accessible_| mode may have changed while the widget was
+    // inactive.
+    AdvanceFocusIfNecessary();
   }
-  return false;
+  return view == focused_view_;
 }
 
 void FocusManager::SetStoredFocusView(View* focus_view) {
@@ -542,4 +556,10 @@ bool FocusManager::ProcessArrowKeyTraversal(const ui::KeyEvent& event) {
   return false;
 }
 
+bool FocusManager::IsFocusable(View* view) const {
+  DCHECK(view);
+  return keyboard_accessible_ ? view->IsAccessibilityFocusable()
+                              : view->IsFocusable();
+}
+
 }  // namespace views