Instead of ArrayBuffer, pass blob with printerProvider.onPrintRequested

extensions/browser/api/printer_provider/printer_provider_api.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_BROWSER_API_PRINTER_PROVIDER_PRINTER_PROVIDER_API_H_
 #define EXTENSIONS_BROWSER_API_PRINTER_PROVIDER_PRINTER_PROVIDER_API_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "components/keyed_service/core/keyed_service.h"
 
 namespace base {
 class DictionaryValue;
 class ListValue;
 }
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
+class Extension;
 struct PrinterProviderPrintJob;
 }
 
 namespace extensions {
 
 // Implements chrome.printerProvider API events.
 class PrinterProviderAPI : public KeyedService {
  public:
   using GetPrintersCallback =
       base::Callback<void(const base::ListValue& printers, bool done)>;
   using GetCapabilityCallback =
       base::Callback<void(const base::DictionaryValue& capability)>;
   using PrintCallback =
       base::Callback<void(bool success, const std::string& error)>;
 
   static PrinterProviderAPI* Create(content::BrowserContext* context);
 
   // Returns generic error string for print request.
   static std::string GetDefaultPrintError();
 
-  // The API currently cannot handle very large files, so the document size that
-  // may be sent to an extension is restricted.
-  // TODO(tbarzic): Fix the API to support huge documents.
-  static const int kMaxDocumentSize = 50 * 1000 * 1000;
-
   ~PrinterProviderAPI() override {}
 
   virtual void DispatchGetPrintersRequested(
       const GetPrintersCallback& callback) = 0;
 
   // Requests printer capability for a printer with id |printer_id|.
   // |printer_id| should be one of the printer ids reported by |GetPrinters|
   // callback.
   // It dispatches chrome.printerProvider.onGetCapabilityRequested event
   // to the extension that manages the printer (which can be determined from
   // |printer_id| value).
   // |callback| is passed a dictionary value containing printer capabilities as
   // reported by the extension.
   virtual void DispatchGetCapabilityRequested(
       const std::string& printer_id,
       const GetCapabilityCallback& callback) = 0;
 
   // It dispatches chrome.printerProvider.onPrintRequested event with the
   // provided print job. The event is dispatched only to the extension that
   // manages printer with id |job.printer_id|.
   // |callback| is passed the print status returned by the extension, and it
   // must not be null.
   virtual void DispatchPrintRequested(const PrinterProviderPrintJob& job,
                                       const PrintCallback& callback) = 0;
+
+  // Returns print job associated with the print request with id |request_id|
+  // for extension |extension|.
+  // It should return NULL if the job for the request does not exist.
+  virtual const PrinterProviderPrintJob* GetPrintJob(const Extension* extension,
+                                                     int request_id) const = 0;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_PRINTER_PROVIDER_PRINTER_PROVIDER_API_H_