Fix include paths for pdfium_unittests under chromium checkout.

Here, testing/gtest and testing/some-pdfium-stuff will be different
directories, since we will use the gtest at top-level.  For standalone,
they happen to be the same.

TBR=bo_xu@foxitsoftware.com

Review URL: https://codereview.chromium.org/852493002
diff --git a/core/src/fxcrt/fx_basic_bstring_unittest.cpp b/core/src/fxcrt/fx_basic_bstring_unittest.cpp
index 030b6ae..53427e3 100644
--- a/core/src/fxcrt/fx_basic_bstring_unittest.cpp
+++ b/core/src/fxcrt/fx_basic_bstring_unittest.cpp
@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 #include "testing/gtest/include/gtest/gtest.h"
-#include "testing/fx_string_testhelpers.h"
+#include "../../../testing/fx_string_testhelpers.h"
 #include "../../include/fxcrt/fx_basic.h"
 
 TEST(fxcrt, ByteStringCNull) {
diff --git a/xfa/src/fxbarcode/pdf417/BC_PDF417HighLevelEncoder_unittest.cpp b/xfa/src/fxbarcode/pdf417/BC_PDF417HighLevelEncoder_unittest.cpp
index 33c8753..01833cf 100644
--- a/xfa/src/fxbarcode/pdf417/BC_PDF417HighLevelEncoder_unittest.cpp
+++ b/xfa/src/fxbarcode/pdf417/BC_PDF417HighLevelEncoder_unittest.cpp
@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "core/include/fxcrt/fx_basic.h"
-#include "BC_PDF417HighLevelEncoder.h"
 #include "testing/gtest/include/gtest/gtest.h"
-#include "testing/fx_string_testhelpers.h"
+#include "../../../../core/include/fxcrt/fx_basic.h"
+#include "../../../../testing/fx_string_testhelpers.h"
+#include "BC_PDF417HighLevelEncoder.h"
 
 TEST(PDF417HighLevelEncoder, EncodeHighLevel) {
   // TODO(tsepez): implement test cases.