scanning: Use page number as is from lorgnette

The page number reported by lorgnette changed from being 0-indexed to
1-indexed. Use the page number as is instead of adding 1 to it.

Bug: 1059779
Change-Id: Ieb52cef8edc25db90e1e13a839f4c2bbf657d471
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2511469Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Jesse Schettler <jschettler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822851}

chrome/browser/chromeos/scanning/fake_lorgnette_scanner_manager.cc

@@ -45,7 +45,7 @@ void FakeLorgnetteScannerManager::Scan(const std::string& scanner_name,
 
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
-        base::BindOnce(page_callback, scan_data_.value(), /*page_number=*/0));
+        base::BindOnce(page_callback, scan_data_.value(), /*page_number=*/1));
   }
 
   base::ThreadTaskRunnerHandle::Get()->PostTask(

chrome/browser/chromeos/scanning/scan_service.cc

@@ -140,11 +140,10 @@ void ScanService::OnPageReceived(const base::FilePath& scan_to_path,
     return;
   }
 
-  // The |page_number| is 0-indexed.
   const std::string filename = base::StringPrintf(
       "scan_%02d%02d%02d-%02d%02d%02d_%d.png", start_time_.year,
       start_time_.month, start_time_.day_of_month, start_time_.hour,
-      start_time_.minute, start_time_.second, page_number + 1);
+      start_time_.minute, start_time_.second, page_number);
   const auto file_path = scan_to_path.Append(filename);
   if (!base::WriteFile(file_path, scanned_image)) {
     LOG(ERROR) << "Failed to save scanned image: " << file_path.value().c_str();