Revert of mash: Remove ChromeLauncherController's |id_to_item_controller_map_|.

ash/common/shelf/shelf_model_unittest.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 "ash/common/shelf/shelf_model.h"
 
 #include <set>
 #include <string>
 
 #include "ash/common/shelf/shelf_model_observer.h"
@@ skipping 19 matching lines @@
     AddToResult("moved=%d", moved_count_, &result);
     added_count_ = removed_count_ = changed_count_ = moved_count_ = 0;
     return result;
   }
 
   // ShelfModelObserver overrides:
   void ShelfItemAdded(int) override { added_count_++; }
   void ShelfItemRemoved(int, const ShelfItem&) override { removed_count_++; }
   void ShelfItemChanged(int, const ShelfItem&) override { changed_count_++; }
   void ShelfItemMoved(int, int) override { moved_count_++; }
+  void OnSetShelfItemDelegate(ShelfID, ShelfItemDelegate*) override {}
 
  private:
   void AddToResult(const std::string& format, int count, std::string* result) {
     if (!count)
       return;
     if (!result->empty())
       *result += " ";
     *result += base::StringPrintf(format.c_str(), count);
   }
 
@@ skipping 244 matching lines @@
   // Now change the type of the second item and make sure that it is moving
   // behind the shortcuts.
   item.type = TYPE_APP;
   model_->Set(app2_index, item);
 
   // The item should have moved in front of the app launcher.
   EXPECT_EQ(TYPE_APP, model_->items()[4].type);
 }
 
 }  // namespace ash