Return unique_ptrs from test_support functions

fpdfsdk/src/fpdfdoc_embeddertest.cpp

 // Copyright 2015 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 "core/include/fxcrt/fx_string.h"
 #include "public/fpdf_doc.h"
 #include "public/fpdfview.h"
 #include "testing/embedder_test.h"
 #include "testing/fx_string_testhelpers.h"
 #include "testing/test_support.h"
@@ skipping 88 matching lines @@
             CFX_WideString::FromUTF16LE(buf, 13));
 
   EXPECT_EQ(nullptr, FPDFBookmark_GetNextSibling(document(), sibling));
 }
 
 TEST_F(FPDFDocEmbeddertest, FindBookmarks) {
   // Open a file with two bookmarks.
   EXPECT_TRUE(OpenDocument("bookmarks.pdf"));
 
   // Find the first one, based on its known title.
-  FPDF_WIDESTRING title = GetFPDFWideString(L"A Good Beginning");
-  FPDF_BOOKMARK child = FPDFBookmark_Find(document(), title);
+  std::unique_ptr<unsigned short, pdfium::FreeDeleter> title =
+      GetFPDFWideString(L"A Good Beginning");
+  FPDF_BOOKMARK child = FPDFBookmark_Find(document(), title.get());
   EXPECT_NE(nullptr, child);
 
   // Check that the string matches.
   unsigned short buf[128];
   EXPECT_EQ(34, FPDFBookmark_GetTitle(child, buf, sizeof(buf)));
   EXPECT_EQ(CFX_WideString(L"A Good Beginning"),
             CFX_WideString::FromUTF16LE(buf, 16));
 
   // Check that it is them same as the one returned by GetFirstChild.
   EXPECT_EQ(child, FPDFBookmark_GetFirstChild(document(), nullptr));
 
   // Try to find one using a non-existent title.
-  FPDF_WIDESTRING bad_title = GetFPDFWideString(L"A BAD Beginning");
-  EXPECT_EQ(nullptr, FPDFBookmark_Find(document(), bad_title));
-
-  // Alas, the typedef includes the "const".
-  free(const_cast<unsigned short*>(title));
-  free(const_cast<unsigned short*>(bad_title));
+  std::unique_ptr<unsigned short, pdfium::FreeDeleter> bad_title =
+      GetFPDFWideString(L"A BAD Beginning");
+  EXPECT_EQ(nullptr, FPDFBookmark_Find(document(), bad_title.get()));
 }