tree 18ac3c6c6bec460458ad519f42cd885595b64f7b
parent e5671979c9d5d77bc2287c7664f8b161835a3627
author Wyatt Hepler <hepler@google.com> 1580493672 -0800
committer Wyatt Hepler <hepler@google.com> 1582916977 -0800

pw_span: Fix deduction guides for containers

Previously, the constness of the container implied the constness of the
elements, which is not always correct. A mutable std::string has mutable
elements, but a mutable std::string_view has const elements. The result
was that template argument deduction failed in some cases, including a
mutable std::string_view.

This change has the container deduction guides use the actual element
type from the container as the element type for the span.

Change-Id: Idafde58b8cfedf86e1f90a3e22fb05780903222e