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

mojo/edk/system/channel_test_base.h

Index: mojo/edk/system/channel_test_base.h
diff --git a/mojo/edk/system/channel_test_base.h b/mojo/edk/system/channel_test_base.h
index 8b1b9326b483fe19822f4c0a1ddd817e2c0e9c9f..6c90c7c400ad3425c8103d7a7b3989f54bce0f94 100644
--- a/mojo/edk/system/channel_test_base.h
+++ b/mojo/edk/system/channel_test_base.h
@@ -11,7 +11,7 @@
 #include "mojo/edk/embedder/simple_platform_support.h"
 #include "mojo/edk/system/channel.h"
 #include "mojo/edk/system/ref_ptr.h"
-#include "mojo/edk/test/test_io_thread.h"
+#include "mojo/edk/system/test/test_io_thread.h"
 #include "mojo/public/cpp/system/macros.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -43,7 +43,7 @@ class ChannelTestBase : public testing::Test {
   void ShutdownChannelOnIOThread(unsigned i);
   void ShutdownAndReleaseChannelOnIOThread(unsigned i);
 
-  mojo::test::TestIOThread* io_thread() { return &io_thread_; }
+  TestIOThread* io_thread() { return &io_thread_; }
   Channel* channel(unsigned i) { return channels_[i].get(); }
   RefPtr<Channel>* mutable_channel(unsigned i) { return &channels_[i]; }
 
@@ -51,7 +51,7 @@ class ChannelTestBase : public testing::Test {
   void SetUpOnIOThread();
 
   embedder::SimplePlatformSupport platform_support_;
-  mojo::test::TestIOThread io_thread_;
+  TestIOThread io_thread_;
   std::unique_ptr<RawChannel> raw_channels_[2];
   RefPtr<Channel> channels_[2];