Add a card background to the app list search result groups.

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 044a251021185c090656b775fa34b7af1f5982c6..af2f5be8c0a361b8bde9b8c27f9bc7873995834a 100644
--- a/ui/app_list/views/start_page_view.cc
+++ b/ui/app_list/views/start_page_view.cc
@@ -129,6 +129,7 @@ void StartPageView::InitTilesContainer() {
   for (size_t i = 0; i < kNumStartPageTiles; ++i) {
     SearchResultTileItemView* tile_item = new SearchResultTileItemView();
     tiles_container_->AddChildView(tile_item);
+    tile_item->SetTitleBackgroundColor(kLabelBackgroundColor);

[Matt Giuca, 2014/11/13 00:17:23]

Let's clarify:

Previously, all TileItemViews had a solid background colour of #f5f5f5. (Same
colour as the background.)

Now, by default TileItemViews have a transparent background, such as is used in
your new SearchCardView (so they are properly painted onto a #ffffff
background). But on the StartPageView, the tile items explicitly have their
background set to #f5f5f5 to preserve the existing behaviour.

Correct? Sounds good, but I'm not sure why they can't just be transparent in the
first place...?

[calamity, 2014/11/13 03:55:31]

Yup. Kinda convoluted but I think it's correct for clients to set the background
color.
For non-CrOS, there are subpixel AA rendering issues when no background color is
retrievable up the view tree inside the layer. (when the text turns all broken)

[Matt Giuca, 2014/11/13 07:10:41]

Acknowledged.

     search_result_tile_views_.push_back(tile_item);
   }
 
@@ -137,6 +138,7 @@ void StartPageView::InitTilesContainer() {
       app_list_main_view_->contents_view(),
       view_delegate_->GetModel()->top_level_item_list());
   all_apps_button_->UpdateIcon();
+  all_apps_button_->SetTitleBackgroundColor(kLabelBackgroundColor);
   tiles_container_->AddChildView(all_apps_button_);
 }