Create public function to get if AccessiblePaneView has focus.

This is used to see if the tab strip has focus for showing tab hover cards during keyboard navigation. This is a follow up to https://chromium-review.googlesource.com/c/chromium/src/+/1612220

Bug: 963537
Change-Id: I8d684255c42007012f599b8a13d6a0fda76665d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1613927Reviewed-by: Michael Wasserman <msw@chromium.org>
Reviewed-by: Dana Fried <dfried@chromium.org>
Commit-Queue: Caroline Rising <corising@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660942}

chrome/browser/ui/views/tabs/tab_strip.cc

@@ -143,7 +143,7 @@ class TabHoverCardEventSniffer : public ui::EventHandler {
  protected:
   // ui::EventTarget:
   void OnKeyEvent(ui::KeyEvent* event) override {
-    if (!TabStripIsKeyboardFocused())
+    if (!tab_strip_->pane_has_focus())
       hover_card_->FadeOutToHide();
   }
 
@@ -153,10 +153,6 @@ class TabHoverCardEventSniffer : public ui::EventHandler {
   }
 
  private:
-  bool TabStripIsKeyboardFocused() {
-    return tab_strip_->GetPaneFocusTraversable() != nullptr;
-  }
-
   TabHoverCardBubbleView* const hover_card_;
   TabStrip* tab_strip_;
   views::Widget* widget_;

ui/views/accessible_pane_view.h

@@ -35,6 +35,8 @@ class VIEWS_EXPORT AccessiblePaneView : public View,
   // the pane was able to receive focus.
   virtual bool SetPaneFocus(View* initial_focus);
 
+  bool pane_has_focus() const { return pane_has_focus_; }
+
   // Set focus to the pane with complete keyboard access, with the
   // focus initially set to the default child. Focus will be restored
   // to the last focused view if the user escapes.