Add padding values to View.idl

sky/engine/public/platform/sky_display_metrics.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 SKY_ENGINE_PUBLIC_SKY_SKY_DISPLAY_METRICS_H_
 #define SKY_ENGINE_PUBLIC_SKY_SKY_DISPLAY_METRICS_H_
 
 #include "sky/engine/public/platform/WebSize.h"
 
 namespace blink {
 
 struct SkyDisplayMetrics {
   WebSize physical_size;
   float device_pixel_ratio = 1.0;
+  double padding_top = 0.0;
+  double padding_right = 0.0;
+  double padding_bottom = 0.0;
+  double padding_left = 0.0;
 };
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_PUBLIC_SKY_SKY_DISPLAY_METRICS_H_