Remove several unneeded includes from mojo/edk/test_utils.h.

TBR=vardhan@google.com

Review URL: https://codereview.chromium.org/1352723002 .

mojo/edk/test/test_utils.h

diff --git a/mojo/edk/test/test_utils.h b/mojo/edk/test/test_utils.h
index fad57ba..72f9257 100644
--- a/mojo/edk/test/test_utils.h
+++ b/mojo/edk/test/test_utils.h
@@ -6,9 +6,6 @@
 #define MOJO_EDK_TEST_TEST_UTILS_H_
 
 #include <stddef.h>
-#include <stdio.h>
-
-#include <string>
 
 #include "mojo/edk/embedder/platform_handle.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"

mojo/edk/test/test_utils_posix.cc

diff --git a/mojo/edk/test/test_utils_posix.cc b/mojo/edk/test/test_utils_posix.cc
index 46f50e2..70c1bde 100644
--- a/mojo/edk/test/test_utils_posix.cc
+++ b/mojo/edk/test/test_utils_posix.cc
@@ -5,6 +5,7 @@
 #include "mojo/edk/test/test_utils.h"
 
 #include <fcntl.h>
+#include <stdio.h>
 #include <unistd.h>
 
 #include "base/logging.h"