Rename traits and mojo directory in //services/viz/public

This CL renames mojo to mojom and *_struct_traits.* to
*_mojom_traits.* in //services/viz/public.

*_struct_traits.* => *_mojom_traits.*
services/viz/public/interfaces => services/viz/public/mojom

Bug: 806965
Change-Id: If8838d8a33c1063b4ce97cc791723a2e89d9f632
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1715488
Commit-Queue: Miyoung Shin <myid.shin@igalia.com>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681628}

diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 80c2ef76..a39b7bb 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn

@@ -831,7 +831,7 @@
     "//media",
     "//mojo/core/embedder",
     "//mojo/public/cpp/bindings",
-    "//services/viz/public/interfaces",
+    "//services/viz/public/mojom",
     "//skia",
     "//testing/gmock",
     "//testing/gtest",