Don't fire a FOCUS accessibility event on a View that doesn't have focus.

ui/app_list/views/start_page_view.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/app_list/views/start_page_view.h"
 
 #include <string>
 
 #include "base/i18n/rtl.h"
 #include "base/macros.h"
@@ skipping 68 matching lines @@
       : selected_(false),
         custom_launcher_page_name_(custom_launcher_page_name) {
     set_background(views::Background::CreateSolidBackground(kSelectedColor));
   }
   ~CustomLauncherPageBackgroundView() override {}
 
   void SetSelected(bool selected) {
     selected_ = selected;
     SetVisible(selected);
     if (selected)
-      NotifyAccessibilityEvent(ui::AX_EVENT_FOCUS, true);
+      NotifyAccessibilityEvent(ui::AX_EVENT_SELECTION, true);

[sky, 2016/02/14 16:21:52]

Do you really only want to notify if selected, or if the selection changes?

[dmazzoni, 2016/02/17 00:25:19]

In this particular case a notification when something is selected seems to work
best we need an explicit notification when you use the arrow keys to choose an
app / result, but we don't if you press a key and that unselects an item because
focus is in the text field and pressing the key is already sending accessibility
events there.

Another way to do this would be to make the relationship between the focused
view and the list of results more explicit (e.g., the focused view's accessible
state could include fields like "active descendant" or "selected children"),
then we could just fire a "something changed" type of event and it'd be possible
for the accessibility client to figure out what happened. I was planning on that
as a possible future improvement, but let me know if you'd prefer something like
that now.

   }
 
   bool selected() { return selected_; }
 
   // Overridden from views::View:
   void GetAccessibleState(ui::AXViewState* state) override {
     state->role = ui::AX_ROLE_BUTTON;
     state->name = base::UTF8ToUTF16(custom_launcher_page_name_);
   }
 
@@ skipping 396 matching lines @@
   // is enabled).
   if (event->type() == ui::ET_SCROLL && event->y_offset() < 0)
     MaybeOpenCustomLauncherPage();
 }
 
 TileItemView* StartPageView::GetTileItemView(size_t index) {
   return tiles_container_->GetTileItemView(index);
 }
 
 }  // namespace app_list