Add keyboard navigation for start page tiles in experimental app list.

ui/app_list/views/start_page_view.cc

Index: ui/app_list/views/start_page_view.cc
diff --git a/ui/app_list/views/start_page_view.cc b/ui/app_list/views/start_page_view.cc
index 4458ea7e244d800c386f5791afc4d6cf4e94e308..ce91eb7fa9d38644451484898e37e6bc2adc294d 100644
--- a/ui/app_list/views/start_page_view.cc
+++ b/ui/app_list/views/start_page_view.cc
@@ -146,6 +146,7 @@ TileItemView* StartPageView::all_apps_button() const {
 
 void StartPageView::OnShow() {
   UpdateCustomPageClickzoneVisibility();
+  ClearSelectedIndex();
 }
 
 void StartPageView::OnHide() {
@@ -163,7 +164,48 @@ void StartPageView::Layout() {
   tiles_container_->SetBoundsRect(bounds);
 }
 
+bool StartPageView::OnKeyPressed(const ui::KeyEvent& event) {
+  if (selected_index() >= 0 &&
+      tiles_container_->child_at(selected_index())->OnKeyPressed(event))

[Matt Giuca, 2014/12/09 08:02:01]

Question: Does this mean the all apps button will work now if you hit enter? Or
not.

If true, then I think you should fix SpokenFeedbackTest (pseudo-revert
https://codereview.chromium.org/762113004/). Or I can do that in a follow-up CL.
(If the all apps button doesn't work, then I will fix that and revert the test
in a follow-up.)

[calamity, 2014/12/10 04:39:46]

Yes.
It wouldn't be a pseudo-revert, you'd need to actually go and select it and
stuff first, changing the things that are in the utterance queue.

[Matt Giuca, 2014/12/10 07:04:28]

OK I will do it.

+    return true;
+
+  int dir = 0;
+  switch (event.key_code()) {
+    case ui::VKEY_LEFT:
+      dir = -1;
+      break;
+    case ui::VKEY_RIGHT:
+      dir = 1;
+      break;
+    case ui::VKEY_DOWN:
+      dir = 1;
+      break;
+    case ui::VKEY_TAB:
+      dir = event.IsShiftDown() ? -1 : 1;
+      break;
+    default:
+      break;
+  }
+
+  if (dir == 0)
+    return false;
+
+  if (!IsValidSelectionIndex(selected_index())) {
+    OnContainerSelected(dir == -1);

[Matt Giuca, 2014/12/09 08:02:01]

I don't really get why you use OnContainerSelected here. I thought OCS was for a
parent container to start moving into this container. But SPV doesn't have a
parent container. You're essentially just using this to get out of an invalid
state (which is unclear to me why you'd be in it). Why should you come up from
the bottom if you were in an invalid state and pressed left?

[calamity, 2014/12/10 04:39:46]

Eh. This is a bit of a semantic choice. I guess we can just put the
functionality here.

FYI, the state is invalid when there's no selection. i.e, on initialization.

+    return true;
+  }
+
+  int selection_index = selected_index() + dir;
+  if (IsValidSelectionIndex(selection_index)) {
+    SetSelectedIndex(selection_index);
+    return true;
+  }
+
+  return false;
+}
+
 void StartPageView::OnContainerSelected(bool from_bottom) {
+  SetSelectedIndex(from_bottom ? num_results() - 1 : 0);
 }
 
 gfx::Rect StartPageView::GetSearchBoxBounds() const {
@@ -201,10 +243,22 @@ int StartPageView::Update() {
 
   tiles_container_->Layout();
   Layout();
-  return display_results.size();
+  // Add 1 to the results size to account for the all apps button.
+  return display_results.size() + 1;

[Matt Giuca, 2014/12/09 08:02:01]

Is this result unrelated?

[calamity, 2014/12/10 04:39:46]

Nope. Necessary to allow the all_apps_button_ to be a valid selection index.

 }
 
 void StartPageView::UpdateSelectedIndex(int old_selected, int new_selected) {
+  if (old_selected >= 0) {
+    tiles_container_->child_at(old_selected)->set_background(nullptr);
+    tiles_container_->child_at(old_selected)->SchedulePaint();
+  }
+
+  if (new_selected >= 0) {
+    tiles_container_->child_at(new_selected)
+        ->set_background(
+            views::Background::CreateSolidBackground(kSelectedColor));
+    tiles_container_->child_at(new_selected)->SchedulePaint();
+  }
 }
 
 }  // namespace app_list