[Chrome OS] Change layout of the launcher.

ui/app_list/search/mixer.cc

 // Copyright 2013 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/search/mixer.h"
 
 #include <algorithm>
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "ui/app_list/search_provider.h"
 #include "ui/app_list/search_result.h"
 
 namespace app_list {
 
 namespace {
 
 // Maximum number of results to show.
-const size_t kMinResults = 6;
+const size_t kMinResults = 9;

[xiyuan, 2016/08/08 18:02:15]

Would this change the search result UI? That is, the mixer generates 6 results
on search but generates 9 now. The result list view only shows the first 6. This
might cause low weight results never get shown.

We probably needs to pass this number from outside, e.g. from SearchController,
as an arg to MixAndPublish, and use 6 for regular search and 9 when the search
is for recommendations (query is empty).

[xdai1, 2016/08/08 21:25:38]

No it doesn't change the search result UI. The number of the search results is
always 8. The reason I changed kMinResults here is because if I don't change it,
the size |display_results| in StartPageView::StartPageTilesContainer::Update()
is always 8, but we need 9... 

[xdai1, 2016/08/08 21:30:08]

kNumSearchResultTiles
(https://cs.chromium.org/chromium/src/ui/app_list/views/search_result_tile_ite...
) is used to control the number of the search results.

[xiyuan, 2016/08/08 21:41:00]

The mixer is applying weight and sort the results based on scores. Certain
provider (such as Webstore result provider) has low priority so that its results
are always at the end of the list. Creating 9 results here while we only show 6
results [1] would cause the results from such provider never show up. 

[1]:
https://cs.chromium.org/chromium/src/ui/app_list/views/search_result_list_vie...

 
 void UpdateResult(const SearchResult& source, SearchResult* target) {
   target->set_display_type(source.display_type());
   target->set_title(source.title());
   target->set_title_tags(source.title_tags());
   target->set_details(source.details());
   target->set_details_tags(source.details_tags());
 }
 
 }  // namespace
@@ skipping 215 matching lines @@
   results->swap(final);
 }
 
 void Mixer::FetchResults(bool is_voice_query,
                          const KnownResults& known_results) {
   for (auto* group : groups_)
     group->FetchResults(is_voice_query, known_results);
 }
 
 }  // namespace app_list