Add NativePixmapHandle type & interface for exporting them

ui/ozone/platform/cast/surface_factory_cast.cc

 // 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.
 
 #include "ui/ozone/platform/cast/surface_factory_cast.h"
 
 #include "base/callback_helpers.h"
 #include "chromecast/public/cast_egl_platform.h"
 #include "chromecast/public/graphics_types.h"
 #include "ui/gfx/geometry/quad_f.h"
@@ skipping 193 matching lines @@
                               int plane_z_order,
                               gfx::OverlayTransform plane_transform,
                               const gfx::Rect& display_bounds,
                               const gfx::RectF& crop_rect) override {
       return true;
     }
     void SetScalingCallback(const ScalingCallback& scaling_callback) override {}
     scoped_refptr<NativePixmap> GetScaledPixmap(gfx::Size new_size) override {
       return nullptr;
     }
+    gfx::NativePixmapHandle ExportHandle() override {
+      return gfx::NativePixmapHandle();
+    }
 
    private:
     ~CastPixmap() override {}
 
     DISALLOW_COPY_AND_ASSIGN(CastPixmap);
   };
   return make_scoped_refptr(new CastPixmap);
 }
 
 bool SurfaceFactoryCast::LoadEGLGLES2Bindings(
@@ skipping 13 matching lines @@
     return false;
   }
 
   set_gl_get_proc_address.Run(gl_proc);
   add_gl_library.Run(lib_egl);
   add_gl_library.Run(lib_gles2);
   return true;
 }
 
 }  // namespace ui