Return unique_ptrs from test_support functions

samples/pdfium_test.cc

Index: samples/pdfium_test.cc
diff --git a/samples/pdfium_test.cc b/samples/pdfium_test.cc
index 9816bb8a31e9069ab64959b853b75ea8b3462bc8..c522a318e60ad5ac82007bdf12a604092694c94d 100644
--- a/samples/pdfium_test.cc
+++ b/samples/pdfium_test.cc
@@ -590,11 +590,10 @@ int main(int argc, const char* argv[]) {
     std::string filename = files.front();
     files.pop_front();
     size_t file_length = 0;
-    char* file_contents = GetFileContents(filename.c_str(), &file_length);
-    if (!file_contents)
-      continue;
-    RenderPdf(filename, file_contents, file_length, options);
-    free(file_contents);
+    std::unique_ptr<char, pdfium::FreeDeleter> file_contents =
+        GetFileContents(filename.c_str(), &file_length);
+    if (file_contents)
+      RenderPdf(filename, file_contents.get(), file_length, options);
   }
 
   FPDF_DestroyLibrary();