Implement window.print() on Android

printing/printing_context.h

 // Copyright (c) 2011 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 PRINTING_PRINTING_CONTEXT_H_
 #define PRINTING_PRINTING_CONTEXT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 20 matching lines @@
     Delegate() {};
     virtual ~Delegate() {};
 
     // Returns parent view to use for modal dialogs.
     virtual gfx::NativeView GetParentView() = 0;
 
     // Returns application locale.
     virtual std::string GetAppLocale() = 0;
   };
 
-  // Tri-state result for user behavior-dependent functions.
+  // Result for user behavior-dependent functions.
   enum Result {
     OK,
     CANCEL,
     FAILED,
+    SYSTEM_DIALOG_DONE,
   };
 
   virtual ~PrintingContext();
 
   // Callback of AskUserForSettings, used to notify the PrintJobWorker when
   // print settings are available.
   typedef base::Callback<void(Result)> PrintSettingsCallback;
 
+  // Called when a printing process initiated by a script finishes.
+  // It's required to synchronize window.print() calls on Android
+  virtual void RequestSystemDialog(const PrintSettingsCallback& cb);
+
   // Asks the user what printer and format should be used to print. Updates the
   // context with the select device settings. The result of the call is returned
   // in the callback. This is necessary for Linux, which only has an
   // asynchronous printing API.
   virtual void AskUserForSettings(int max_pages,
                                   bool has_selection,
                                   const PrintSettingsCallback& callback) = 0;
 
   // Selects the user's default printer and format. Updates the context with the
   // default device settings.
@@ skipping 80 matching lines @@
   // Did the user cancel the print job.
   volatile bool abort_printing_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PrintingContext);
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_PRINTING_CONTEXT_H_