Instead of ArrayBuffer, pass blob with printerProvider.onPrintRequested

content/browser/fileapi/chrome_blob_storage_context.h

Index: content/browser/fileapi/chrome_blob_storage_context.h
diff --git a/content/browser/fileapi/chrome_blob_storage_context.h b/content/browser/fileapi/chrome_blob_storage_context.h
index 8d8a5f226b47b4507f79b023645498597cf98e03..0c565459a2cf052e2e159132e972025fbe7fed73 100644
--- a/content/browser/fileapi/chrome_blob_storage_context.h
+++ b/content/browser/fileapi/chrome_blob_storage_context.h
@@ -10,6 +10,11 @@
 #include "base/sequenced_task_runner_helpers.h"
 #include "content/common/content_export.h"
 
+namespace base {
+class FilePath;
+class Time;
+}
+
 namespace storage {
 class BlobStorageContext;
 }
@@ -43,6 +48,13 @@ class CONTENT_EXPORT ChromeBlobStorageContext
   scoped_ptr<BlobHandle> CreateMemoryBackedBlob(const char* data,
                                                 size_t length);
 
+  // Returns a NULL scoped_ptr on failure.
+  scoped_ptr<BlobHandle> CreateFileBackedBlob(
+      const base::FilePath& path,
+      int64_t offset,
+      int64_t size,
+      const base::Time& expected_modification_time);
+
  protected:
   virtual ~ChromeBlobStorageContext();