Move ViewMsg_New to mojom

This is added to a new content::mojom::Renderer interface which
is intended to define any messages processed directly by
RenderThreadImpl.

Also moves ViewMsg_New_Params to a mojom struct and adds
native typemaps for some of its dependencies.

BUG=612500
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2381493003
Cr-Commit-Position: refs/heads/master@{#422236}
30 files changed