Merge to XFA: Remove relative includes.

That refer to parent directories.

TBR=dsinclair@chromium.org

Review URL: https://codereview.chromium.org/1434223002 .

(cherry picked from commit 22bc4227fbbda5a5e9abad2a2c0a98c04fe7f228)

Review URL: https://codereview.chromium.org/1439223003 .
diff --git a/samples/pdfium_test.cc b/samples/pdfium_test.cc
index 3e71a60..8162287 100644
--- a/samples/pdfium_test.cc
+++ b/samples/pdfium_test.cc
@@ -14,13 +14,13 @@
 #include <utility>
 #include <vector>
 
-#include "../testing/test_support.h"
 #include "image_diff_png.h"
 #include "public/fpdf_dataavail.h"
 #include "public/fpdf_ext.h"
 #include "public/fpdf_formfill.h"
 #include "public/fpdf_text.h"
 #include "public/fpdfview.h"
+#include "testing/test_support.h"
 
 #ifdef PDF_ENABLE_V8
 #include "v8/include/libplatform/libplatform.h"