Rename traits in //gpu

This CL renames *_struct_traits.* to *_mojom_traits.* in //gpu.

*_struct_traits.* => *_mojom_traits.*

Bug: 806965
Change-Id: I7c31344d154b3d7390a8c9f92997cfb8fb868657
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1728413
Commit-Queue: Miyoung Shin <myid.shin@igalia.com>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: Eric Karl <ericrk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683026}

diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 7b4b28b..d9ecd6d 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn

@@ -827,7 +827,7 @@
     "//gpu/command_buffer/client:raster",
     "//gpu/command_buffer/client:raster_interface",
     "//gpu/ipc:gl_in_process_context",
-    "//gpu/ipc/common:struct_traits",
+    "//gpu/ipc/common:mojom_traits",
     "//media",
     "//mojo/core/embedder",
     "//mojo/public/cpp/bindings",