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

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 "base/strings/utf_string_conversions.h"
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/app_list_item.h"
 #include "ui/app_list/app_list_model.h"
@@ skipping 111 matching lines @@
   views::BoxLayout* tiles_layout_manager =
       new views::BoxLayout(views::BoxLayout::kHorizontal, 0, 0, kTileSpacing);
   tiles_layout_manager->set_main_axis_alignment(
       views::BoxLayout::MAIN_AXIS_ALIGNMENT_CENTER);
   tiles_container_->SetLayoutManager(tiles_layout_manager);
 
   // Add SearchResultTileItemViews to the container.
   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);
   }
 
   // Also add a special "all apps" button to the end of the container.
   all_apps_button_ = new AllAppsTileItemView(
       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_);
 }
 
 void StartPageView::Reset() {
   // This can be called when the app list is closing (widget is invisible). In
   // that case, do not steal focus from other elements.
   if (GetWidget() && GetWidget()->IsVisible())
     search_box_view_->search_box()->RequestFocus();
 
   search_box_view_->ClearSearch();
@@ skipping 39 matching lines @@
 
 void StartPageView::QueryChanged(SearchBoxView* sender) {
   // Forward the search terms on to the real search box and clear the dummy
   // search box.
   app_list_main_view_->OnStartPageSearchTextfieldChanged(
       sender->search_box()->text());
   sender->search_box()->SetText(base::string16());
 }
 
 }  // namespace app_list