base: Remove using declaration from test_suite.h header.

remoting/test/app_remoting_test_driver.cc

Index: remoting/test/app_remoting_test_driver.cc
diff --git a/remoting/test/app_remoting_test_driver.cc b/remoting/test/app_remoting_test_driver.cc
index 57f2947017bc22435c7f517d3f87af1965893129..0d8af2b3a73c2cf14fc7465019edb85a750e7ddb 100644
--- a/remoting/test/app_remoting_test_driver.cc
+++ b/remoting/test/app_remoting_test_driver.cc
@@ -120,7 +120,7 @@ void PrintAuthCodeInfo() {
 
 int main(int argc, char** argv) {
   testing::InitGoogleTest(&argc, argv);
-  TestSuite test_suite(argc, argv);
+  base::TestSuite test_suite(argc, argv);
 
   // The pointer returned here refers to a singleton, since we don't own the
   // lifetime of the object, don't wrap in a scoped_ptr construct or release it.