Add debug to FilesApp ImportContainer call

If import fails for any reason such as being disallowed by policy,
it is helpful to log the result code.

TBR=juwa@google.com

Bug: 1003944
Change-Id: I38eff42f2981a8c166b1d7f4708879f1f3497de7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808949Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Auto-Submit: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697862}

chrome/browser/chromeos/extensions/file_manager/private_api_misc.cc

@@ -723,7 +723,15 @@ FileManagerPrivateInternalImportCrostiniImageFunction::Run() {
   crostini::CrostiniExportImport::GetForProfile(profile)->ImportContainer(
       crostini::ContainerId{crostini::kCrostiniDefaultVmName,
                             crostini::kCrostiniDefaultContainerName},
-      path, base::DoNothing());
+      path,
+      base::BindOnce(
+          [](base::FilePath path, crostini::CrostiniResult result) {
+            if (result != crostini::CrostiniResult::SUCCESS) {
+              LOG(ERROR) << "Error importing crostini image " << path.value()
+                         << ": " << (int)result;
+            }
+          },
+          path));
   return RespondNow(NoArguments());
 }