Add cc::SurfaceInfo::is_valid()

cc/ipc/surface_info_struct_traits.h

Index: cc/ipc/surface_info_struct_traits.h
diff --git a/cc/ipc/surface_info_struct_traits.h b/cc/ipc/surface_info_struct_traits.h
index b1484f829cb28eb9482ffc473b1f05699d9f553e..8b032e311d2a79f71f6e9b6e94b510d94cca27a6 100644
--- a/cc/ipc/surface_info_struct_traits.h
+++ b/cc/ipc/surface_info_struct_traits.h
@@ -27,7 +27,7 @@ struct StructTraits<cc::mojom::SurfaceInfoDataView, cc::SurfaceInfo> {
   static bool Read(cc::mojom::SurfaceInfoDataView data, cc::SurfaceInfo* out) {
     out->device_scale_factor_ = data.device_scale_factor();
     return data.ReadSurfaceId(&out->id_) &&
-           data.ReadSizeInPixels(&out->size_in_pixels_);
+           data.ReadSizeInPixels(&out->size_in_pixels_) && out->is_valid();

[Fady Samuel, 2017/02/28 02:54:32]

I'm not sure if compilers are guaranteed to process these conditions in order.

Do this:

out->device_scale_factor_ = data.device_scale_factor();
if (!data.ReadSurfaceId(&out->id_))
  return false;

if (!data.ReadSizeInPixels(&out->size_in_pixels_))
  return false;

return out->is_valid();

[Tom Sepez, 2017/02/28 17:52:01]

This is fine; sequence points in C occur at the end of the evaluation of the
right operand of a && expression.

   }
 };