[NTP] Automated test that FileSelected updates last selected directory

Writing a test for the new feature remembering the last selected
directory for user. This unit test is for CL:
1162712:[NTP] Upload file from the most recent directory

Bug: 871703
Change-Id: I18769a34ae360ff9b51241178c0e9ffdfd6f8c29
Reviewed-on: https://chromium-review.googlesource.com/1171880Reviewed-by: Kristi Park <kristipark@chromium.org>
Commit-Queue: Weilun Shi <sweilun@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582660}

chrome/browser/ui/search/search_tab_helper.h

@@ -79,6 +79,8 @@ class SearchTabHelper : public content::WebContentsObserver,
                            ChromeIdentityCheckSignedOutMismatch);
   FRIEND_TEST_ALL_PREFIXES(SearchTabHelperTest, HistorySyncCheckSyncing);
   FRIEND_TEST_ALL_PREFIXES(SearchTabHelperTest, HistorySyncCheckNotSyncing);
+  FRIEND_TEST_ALL_PREFIXES(SearchTabHelperTest,
+                           FileSelectedUpdatesLastSelectedDirectory);
 
   explicit SearchTabHelper(content::WebContents* web_contents);
 

chrome/browser/ui/search/search_tab_helper_unittest.cc

@@ -234,6 +234,19 @@ TEST_F(SearchTabHelperTest, HistorySyncCheckNotSyncing) {
   EXPECT_FALSE(search_tab_helper->HistorySyncCheck());
 }
 
+TEST_F(SearchTabHelperTest, FileSelectedUpdatesLastSelectedDirectory) {
+  NavigateAndCommit(GURL(chrome::kChromeUINewTabURL));
+  SearchTabHelper* search_tab_helper =
+      SearchTabHelper::FromWebContents(web_contents());
+  ASSERT_NE(nullptr, search_tab_helper);
+
+  base::FilePath filePath =
+      base::FilePath::FromUTF8Unsafe("a/b/c/Picture/kitten.png");
+  search_tab_helper->FileSelected(filePath, 0, {});
+  Profile* profile = search_tab_helper->profile();
+  EXPECT_EQ(filePath.DirName(), profile->last_selected_directory());
+}
+
 TEST_F(SearchTabHelperTest, TitleIsSetForNTP) {
   NavigateAndCommit(GURL(chrome::kChromeUINewTabURL));
   EXPECT_EQ(l10n_util::GetStringUTF16(IDS_NEW_TAB_TITLE),