We have the same set of bit-flags defined twice:
- public/common/frame/sandbox_flags.h (enum class WebSandboxFlags: int)
- renderer/core/frame/sandbox_flags.h (enum SandboxFlag)

We should get rid of the duplicate here, don't need both.  The second one is older and not typesafe, so we should get rid of this.

Should be doable by search/replace:
kSandboxNone => static_cast<int>(WebSandboxFlags::kNone)
etc.