Give up focus if the focused view becomes unfocusable

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index f74d0f9e79014748448da8bbece2de023ab2217d..5562a2252a276dcc6e3caa767eb30d1f87fcefae 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -454,6 +454,13 @@ void View::SetVisible(bool visible) {
 
     visible_ = visible;
 
+    if (!visible) {

[sky, 2013/12/07 00:29:13]

You have this code in a bunch of places. I think what you should do is create a
method something like, MoveFocusIfNecessary() that roughly does:

if (IsAccessibilityFocusable() || !Contains(focus_view))
  return;

focus_manager->AdvanceFocus(true);
if (Contains(focus_view))
  focus_manager->ClearFocus();

And write tests for this.

[mohsen, 2013/12/11 20:10:12]

I have extracted the common code and moved it to the FocusManager. This way, it
becomes much simpler and there is no need to see if this view (in some cases) is
equal to the focused view or (in other cases) contains the focused view. 

However, I still clear the focus instead of moving it to another view, as it
seems more natural to me. For example, if the user is typing in a textfield and,
for whatever reason, the textfield gets disabled, I think it is better to clear
the focus instead of moving the focus to another view, because the user may not
notice the change and continue typing and possibly override the other view's
data! But, if you think it is better to move focus to another view, it can be
done easily.

+      // If the View has focus or contains the focused view, clear focus.
+      FocusManager* focus_manager = GetFocusManager();
+      if (focus_manager && Contains(focus_manager->GetFocusedView()))
+        focus_manager->ClearFocus();
+    }
+
     // Notify the parent.
     if (parent_)
       parent_->ChildVisibilityChanged(this);
@@ -475,6 +482,12 @@ bool View::IsDrawn() const {
 void View::SetEnabled(bool enabled) {
   if (enabled != enabled_) {
     enabled_ = enabled;
+    if (!enabled) {
+      // If the View has focus, clear focus.
+      FocusManager* focus_manager = GetFocusManager();
+      if (focus_manager && focus_manager->GetFocusedView() == this)
+        focus_manager->ClearFocus();
+    }
     OnEnabledChanged();
   }
 }
@@ -1205,6 +1218,16 @@ void View::SetNextFocusableView(View* view) {
   next_focusable_view_ = view;
 }
 
+void View::SetFocusable(bool focusable) {
+  focusable_ = focusable;
+  if (!focusable && !IsAccessibilityFocusable()) {
+    // If the View has focus, clear focus.
+    FocusManager* focus_manager = GetFocusManager();
+    if (focus_manager && focus_manager->GetFocusedView() == this)
+      focus_manager->ClearFocus();
+  }
+}
+
 bool View::IsFocusable() const {
   return focusable_ && enabled_ && IsDrawn();
 }
@@ -1213,6 +1236,16 @@ bool View::IsAccessibilityFocusable() const {
   return (focusable_ || accessibility_focusable_) && enabled_ && IsDrawn();
 }
 
+void View::SetAccessibilityFocusable(bool accessibility_focusable) {
+  accessibility_focusable_ = accessibility_focusable;
+  if (!accessibility_focusable && !IsFocusable()) {
+    // If the View has focus, clear focus.
+    FocusManager* focus_manager = GetFocusManager();
+    if (focus_manager && focus_manager->GetFocusedView() == this)
+      focus_manager->ClearFocus();
+  }
+}
+
 FocusManager* View::GetFocusManager() {
   Widget* widget = GetWidget();
   return widget ? widget->GetFocusManager() : NULL;