The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/198b9e6b983a55bcce7bc299a4fde8c8611ef6f8

commit 198b9e6b983a55bcce7bc299a4fde8c8611ef6f8
Author: weidongg <weidongg@chromium.org>
Date: Fri Jun 23 22:14:26 2017

Show separator in SearchResultTileItemListView

This CL makes following changes:
1. Add ResultType enum to SearchResult.
2. Add separator between SearchResults of different ResultType in
SearchResultTileItemListView.

The assumption is that the SearchResults are already grouped based on
the ResultType, so we don't need to sort them in this CL.

specs: https://screenshot.googleplex.com/5FKt8ZRembk
screenshot: https://screenshot.googleplex.com/L8URwj8bWQo

BUG= 736157 

Review-Url: https://codereview.chromium.org/2949413002
Cr-Commit-Position: refs/heads/master@{#482045}

[modify] https://crrev.com/198b9e6b983a55bcce7bc299a4fde8c8611ef6f8/chrome/browser/ui/app_list/search/app_result.cc
[modify] https://crrev.com/198b9e6b983a55bcce7bc299a4fde8c8611ef6f8/ui/app_list/app_list_constants.cc
[modify] https://crrev.com/198b9e6b983a55bcce7bc299a4fde8c8611ef6f8/ui/app_list/app_list_constants.h
[modify] https://crrev.com/198b9e6b983a55bcce7bc299a4fde8c8611ef6f8/ui/app_list/search_result.h
[modify] https://crrev.com/198b9e6b983a55bcce7bc299a4fde8c8611ef6f8/ui/app_list/views/search_result_tile_item_list_view.cc
[modify] https://crrev.com/198b9e6b983a55bcce7bc299a4fde8c8611ef6f8/ui/app_list/views/search_result_tile_item_list_view.h
[modify] https://crrev.com/198b9e6b983a55bcce7bc299a4fde8c8611ef6f8/ui/app_list/views/search_result_tile_item_view.cc