cros: Add AppList gesture tap autocomplete

Allow AppList autocomplete to complete suggestions
if SearchBoxView recieves a tap gesture event.
Approved by UX.

Bug: 881617
Change-Id: Ic282fef7623c2f9199d9022289d70e96d3f0111a
Reviewed-on: https://chromium-review.googlesource.com/1212085Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Commit-Queue: Daniel Zhang <oxyflush@google.com>
Cr-Commit-Position: refs/heads/master@{#589568}

ash/app_list/views/search_box_view.cc

@@ -553,6 +553,14 @@ bool SearchBoxView::HandleMouseEvent(views::Textfield* sender,
   return search_box::SearchBoxViewBase::HandleMouseEvent(sender, mouse_event);
 }
 
+bool SearchBoxView::HandleGestureEvent(views::Textfield* sender,
+                                       const ui::GestureEvent& gesture_event) {
+  if (gesture_event.type() == ui::ET_GESTURE_TAP)
+    AcceptAutocompleteText();
+  return search_box::SearchBoxViewBase::HandleGestureEvent(sender,
+                                                           gesture_event);
+}
+
 void SearchBoxView::ButtonPressed(views::Button* sender,
                                   const ui::Event& event) {
   search_box::SearchBoxViewBase::ButtonPressed(sender, event);

ash/app_list/views/search_box_view.h

@@ -122,6 +122,8 @@ class APP_LIST_EXPORT SearchBoxView : public search_box::SearchBoxViewBase,
                       const ui::KeyEvent& key_event) override;
   bool HandleMouseEvent(views::Textfield* sender,
                         const ui::MouseEvent& mouse_event) override;
+  bool HandleGestureEvent(views::Textfield* sender,
+                          const ui::GestureEvent& gesture_event) override;
 
   // Overridden from SearchBoxModelObserver:
   void HintTextChanged() override;