Call base implementation from SearchBoxImageButton::OnFocus

View::OnFocus has logic that should not be skipped for
SearchBoxImageButton - for example, it sends focus change notification
to accessibility stack.

BUG=1113884

Change-Id: I0f14833b9b0158f0fb25c8876ea45b84a74d42d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2481551Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818116}

ash/search_box/search_box_view_base.cc

@@ -119,9 +119,15 @@ class SearchBoxImageButton : public views::ImageButton {
     return Button::OnKeyPressed(event);
   }
 
-  void OnFocus() override { SchedulePaint(); }
+  void OnFocus() override {
+    views::ImageButton::OnFocus();
+    SchedulePaint();
+  }
 
-  void OnBlur() override { SchedulePaint(); }
+  void OnBlur() override {
+    views::ImageButton::OnBlur();
+    SchedulePaint();
+  }
 
   // views::InkDropHostView:
   std::unique_ptr<views::InkDropRipple> CreateInkDropRipple() const override {