Implement window.print() on Android

chrome/browser/printing/print_job_worker.h

 // Copyright (c) 2012 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 CHROME_BROWSER_PRINTING_PRINT_JOB_WORKER_H_
 #define CHROME_BROWSER_PRINTING_PRINT_JOB_WORKER_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 21 matching lines @@
 // PrintJob always outlives its worker instance.
 class PrintJobWorker {
  public:
   PrintJobWorker(int render_process_id,
                  int render_view_id,
                  PrintJobWorkerOwner* owner);
   virtual ~PrintJobWorker();
 
   void SetNewOwner(PrintJobWorkerOwner* new_owner);
 
-  // Initializes the print settings. If |ask_user_for_settings| is true, a
-  // Print... dialog box will be shown to ask the user his preference.
+  // Initializes the print settings. If |ask_settings_type| is ASK_USER, a
+  // Print... dialog box will be shown by the browser to ask the user his
+  // preference. If it is SYSTEM_SPECIFIC, showing that dialog box will be

[mlamouri (slow - plz ping), 2014/11/27 20:26:02]

I do not understand why this is needed.

[dgn, 2014/11/28 11:51:15]

Updated the comment. I tried to address that in more in depth in the CL
description. 

+  // delegated to the system.
   void GetSettings(
-      bool ask_user_for_settings,
+      GetSettingsAskParam ask_settings_type,
       int document_page_count,
       bool has_selection,
       MarginType margin_type);
 
   // Set the new print settings.
   void SetSettings(scoped_ptr<base::DictionaryValue> new_settings);
 
   // Starts the printing loop. Every pages are printed as soon as the data is
   // available. Makes sure the new_document is the right one.
   void StartPrinting(PrintedDocument* new_document);
@@ skipping 52 matching lines @@
   // but sticks with this for consistency.
   void GetSettingsWithUI(
       int document_page_count,
       bool has_selection);
 
   // The callback used by PrintingContext::GetSettingsWithUI() to notify this
   // object that the print settings are set.  This is needed in order to bounce
   // back into the IO thread for GetSettingsDone().
   void GetSettingsWithUIDone(PrintingContext::Result result);
 
+  // Called on the UI thread to ask the system to show a print dialog.
+  void ShowSystemDialog();
+
   // Called on the UI thread to update the print settings.
   void UpdatePrintSettings(scoped_ptr<base::DictionaryValue> new_settings);
 
   // Reports settings back to owner_.
   void GetSettingsDone(PrintingContext::Result result);
 
   // Use the default settings. When using GTK+ or Mac, this can still end up
   // displaying a dialog. So this needs to happen from the UI thread on these
   // systems.
   void UseDefaultSettings();
@@ skipping 22 matching lines @@
 
   // Used to generate a WeakPtr for callbacks.
   base::WeakPtrFactory<PrintJobWorker> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintJobWorker);
 };
 
 }  // namespace printing
 
 #endif  // CHROME_BROWSER_PRINTING_PRINT_JOB_WORKER_H_