Set browser state builder dir to avoid file leaks in ios tests in /ios/chrome/browser/ui/settings

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R=sczs@chromium.org

Bug: 546640
Change-Id: I4d5d350ef28adaf572af0b94024ca4f6549a4548
Fixed: 1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1993141
Commit-Queue: Oliver Li <olivierli@chromium.org>
Auto-Submit: Oliver Li <olivierli@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#730018}

ios/chrome/browser/ui/settings/search_engine_table_view_controller_unittest.mm

@@ -7,6 +7,7 @@
 #include <memory>
 
 #include "base/compiler_specific.h"
+#include "base/files/scoped_temp_dir.h"
 #include "base/mac/foundation_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
@@ -64,6 +65,10 @@ class SearchEngineTableViewControllerTest
   void SetUp() override {
     ChromeTableViewControllerTest::SetUp();
     TestChromeBrowserState::Builder test_cbs_builder;
+
+    ASSERT_TRUE(state_dir_.CreateUniqueTempDir());
+    test_cbs_builder.SetPath(state_dir_.GetPath());
+
     test_cbs_builder.AddTestingFactory(
         ios::TemplateURLServiceFactory::GetInstance(),
         ios::TemplateURLServiceFactory::GetDefaultFactory());
@@ -223,6 +228,11 @@ class SearchEngineTableViewControllerTest
         base::test::ios::kWaitForUIElementTimeout, condition);
   }
 
+  // A state directory that outlives |task_environment_| is needed because
+  // CreateHistoryService/CreateBookmarkModel use the directory to host
+  // databases. See https://crbug.com/546640 for more details.
+  base::ScopedTempDir state_dir_;
+
   web::WebTaskEnvironment task_environment_;
   std::unique_ptr<TestChromeBrowserState> chrome_browser_state_;
   base::HistogramTester histogram_tester_;