Move scoped_test_dir.* and test_io_thread.* from edk/test to edk/system/test.

mojo/edk/system/data_pipe_impl_unittest.cc

Index: mojo/edk/system/data_pipe_impl_unittest.cc
diff --git a/mojo/edk/system/data_pipe_impl_unittest.cc b/mojo/edk/system/data_pipe_impl_unittest.cc
index 22258519a995921b71f061498e55210f9ce187dd..5fbd20e1b0d6b5c35f27ec5f15e8f4dc375009c5 100644
--- a/mojo/edk/system/data_pipe_impl_unittest.cc
+++ b/mojo/edk/system/data_pipe_impl_unittest.cc
@@ -27,9 +27,9 @@
 #include "mojo/edk/system/raw_channel.h"
 #include "mojo/edk/system/ref_ptr.h"
 #include "mojo/edk/system/test/sleep.h"
+#include "mojo/edk/system/test/test_io_thread.h"
 #include "mojo/edk/system/test/timeouts.h"
 #include "mojo/edk/system/waiter.h"
-#include "mojo/edk/test/test_io_thread.h"
 #include "mojo/public/cpp/system/macros.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -224,7 +224,7 @@ class LocalDataPipeImplTestHelper : public DataPipeImplTestHelper {
 class RemoteDataPipeImplTestHelper : public DataPipeImplTestHelper {
  public:
   RemoteDataPipeImplTestHelper()
-      : io_thread_(mojo::test::TestIOThread::StartMode::AUTO) {}
+      : io_thread_(test::TestIOThread::StartMode::AUTO) {}
   ~RemoteDataPipeImplTestHelper() override {}
 
   void SetUp() override {
@@ -345,7 +345,7 @@ class RemoteDataPipeImplTestHelper : public DataPipeImplTestHelper {
   }
 
   embedder::SimplePlatformSupport platform_support_;
-  mojo::test::TestIOThread io_thread_;
+  test::TestIOThread io_thread_;
   RefPtr<Channel> channels_[2];
   RefPtr<MessagePipe> message_pipes_[2];