Out-of-process file patcher: DCHECK the files in the utility process

chrome/utility/chrome_content_utility_client.cc

Index: chrome/utility/chrome_content_utility_client.cc
diff --git a/chrome/utility/chrome_content_utility_client.cc b/chrome/utility/chrome_content_utility_client.cc
index 1e013333a9f040790e9720625fb07334929f33e4..58eeb6269b075b2182667140124ffeeba4a449ba 100644
--- a/chrome/utility/chrome_content_utility_client.cc
+++ b/chrome/utility/chrome_content_utility_client.cc
@@ -84,6 +84,10 @@ class FilePatcherImpl : public chrome::mojom::FilePatcher {
                        base::File patch_file,
                        base::File output_file,
                        const PatchFileBsdiffCallback& callback) override {
+    DCHECK(input_file.IsValid());
+    DCHECK(patch_file.IsValid());
+    DCHECK(output_file.IsValid());
+
     const int patch_result_status = bsdiff::ApplyBinaryPatch(
         std::move(input_file), std::move(patch_file), std::move(output_file));
     callback.Run(patch_result_status);
@@ -93,6 +97,10 @@ class FilePatcherImpl : public chrome::mojom::FilePatcher {
                           base::File patch_file,
                           base::File output_file,
                           const PatchFileCourgetteCallback& callback) override {
+    DCHECK(input_file.IsValid());
+    DCHECK(patch_file.IsValid());
+    DCHECK(output_file.IsValid());
+
     const int patch_result_status = courgette::ApplyEnsemblePatch(
         std::move(input_file), std::move(patch_file), std::move(output_file));
     callback.Run(patch_result_status);