Backport some tests in...

Backport some tests in /chrome/browser/data_reduction_proxy/data_reduction_proxy_settings_unittest_android.cc to SingleThreadTaskEnvironment

These tests were previously migrated from single-threaded MessageLoop to
a multi-threaded TaskEnvironment (then named ScopedTaskEnvironment) as
part of crbug.com/891670.

//base OWNERS decided in retrospect that it was better to keep a
single-threaded option for TaskEnvironment and introduced
SingleThreadTaskEnvironment. This CL retrofits that decision for
/chrome/browser/data_reduction_proxy/data_reduction_proxy_settings_unittest_android.cc.

This CL is a no-op if it passes CQ.

This CL was uploaded by git cl split.

R=tedchoc@chromium.org

Bug: 891670
Change-Id: I6a9cfabe01109bb1979a813f3427fcb482ca08da
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1786966
Auto-Submit: Gabriel Charette <gab@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#694563}

chrome/browser/data_reduction_proxy/data_reduction_proxy_settings_unittest_android.cc

@@ -183,8 +183,8 @@ class DataReductionProxySettingsAndroidTest : public ::testing::Test {
   }
 
  private:
-  base::test::TaskEnvironment task_environment_{
-      base::test::TaskEnvironment::MainThreadType::IO};
+  base::test::SingleThreadTaskEnvironment task_environment_{
+      base::test::SingleThreadTaskEnvironment::MainThreadType::IO};
   JNIEnv* env_;
   net::MockClientSocketFactory mock_socket_factory_;
   std::unique_ptr<data_reduction_proxy::DataReductionProxyTestContext>