views: Rename IsFocusableInRootView() to just IsFocusable().

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index 244f261bc5f14df73204aadc62280b103238f7f5..f260e37961559c75a7d47b296d239536b69e9910 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -894,7 +894,7 @@ void View::SetNextFocusableView(View* view) {
   next_focusable_view_ = view;
 }
 
-bool View::IsFocusableInRootView() const {
+bool View::IsFocusable() const {
   return focusable_ && enabled_ && IsDrawn();
 }
 
@@ -914,7 +914,7 @@ const FocusManager* View::GetFocusManager() const {
 
 void View::RequestFocus() {
   FocusManager* focus_manager = GetFocusManager();
-  if (focus_manager && IsFocusableInRootView())
+  if (focus_manager && IsFocusable())
     focus_manager->SetFocusedView(this);
 }