Add GetScrollOffset function to PPB_View

ppapi/cpp/view.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 PPAPI_CPP_VIEW_H_
 #define PPAPI_CPP_VIEW_H_
 
 #include "ppapi/cpp/resource.h"
 #include "ppapi/cpp/rect.h"
 #include "ppapi/cpp/size.h"
@@ skipping 120 matching lines @@
   /// pixels per DIP.
   float GetDeviceScale() const;
 
   /// GetCSSScale returns the scale factor between DIPs and CSS pixels. This
   /// allows proper scaling between DIPs - as sent via the Pepper API - and CSS
   /// pixel coordinates used for Web content.
   ///
   /// @return A <code>float</code> value representing the number of DIPs per CSS
   /// pixel.
   float GetCSSScale() const;
+
+  /// GetScrollOffset returns the scroll offset of the window containing the
+  /// plugin. This value will only be valid if the module instance is visible
+  /// (that is, IsVisible() is true) otherwise (0, 0) will be returned.
+  ///
+  /// @return A <code>Point</code> which is set to the value of the scroll
+  /// offset in CSS pixels.
+  Point GetScrollOffset() const;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_VIEW_H_