Remove relative includes.

core/src/fxcrt/fx_basic_wstring_unittest.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "../../../testing/fx_string_testhelpers.h"
 #include "core/include/fxcrt/fx_basic.h"
+#include "testing/fx_string_testhelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 TEST(fxcrt, WideStringOperatorSubscript) {
   // CFX_WideString includes the NUL terminator for non-empty strings.
   CFX_WideString abc(L"abc");
   EXPECT_EQ(L'a', abc[0]);
   EXPECT_EQ(L'b', abc[1]);
   EXPECT_EQ(L'c', abc[2]);
   EXPECT_EQ(L'\0', abc[3]);
 }
@@ skipping 492 matching lines @@
     str.Format(L"%0f", 1.12345);
     EXPECT_EQ(L"1.123450", str);
   }
 
   {
     CFX_WideString str;
     str.Format(L"%.1048576f", 1.2);
     EXPECT_EQ(L"Bad precision", str);
   }
 }