Add unit test for Mixer::Publish.

chrome/browser/ui/app_list/search/mixer.h

Index: chrome/browser/ui/app_list/search/mixer.h
diff --git a/chrome/browser/ui/app_list/search/mixer.h b/chrome/browser/ui/app_list/search/mixer.h
index b195d6371a842ff4ba2d554ee6a3f19aa4713845..f47c2d923866c7afe393266a0d0325dd4c2fd95a 100644
--- a/chrome/browser/ui/app_list/search/mixer.h
+++ b/chrome/browser/ui/app_list/search/mixer.h
@@ -12,6 +12,7 @@
 
 namespace app_list {
 
+class ChromeSearchResult;
 class SearchProvider;
 
 // Mixer collects results from providers, sorts them and publishes them to the
@@ -22,6 +23,17 @@ class SearchProvider;
 // slots. The omnibox group takes all the remaining slots.
 class Mixer {
  public:
+  // Used for sorting and mixing results.
+  struct SortData {
+    SortData();
+    SortData(ChromeSearchResult* result, double score);
+
+    bool operator<(const SortData& other) const;
+
+    ChromeSearchResult* result;  // Not owned.
+    double score;
+  };
+
   // The enum represents mixer groups. Note this must matches the order
   // of group creation in Init().
   enum GroupId {
@@ -43,6 +55,11 @@ class Mixer {
   // Collects the results, sorts and publishes them.
   void MixAndPublish(const KnownResults& known_results);
 
+  // Publishes the given |results| to |ui_results|. Reuse existing ones to avoid
+  // flickering.
+  static void Publish(const std::vector<SortData>& results,

[Matt Giuca, 2014/07/08 01:48:23]

I think the standard practice here would be to make SortData and Publish private
and add MixerTest as a friend.

[calamity, 2014/07/08 04:23:00]

Done-ish. SortData still needs to be public to be constructible by the test.
Friendliness doesn't extend to subclasses.

[Matt Giuca, 2014/07/08 05:31:45]

Use FRIEND_TEST_ALL_PREFIXES to actually friend the test class, not the base
class.

+                      AppListModel::SearchResults* ui_results);
+
  private:
   class Group;
   typedef ScopedVector<Group> Groups;