[mojo] include mojo header in /chrome/browser/chromeos/arc/video

This is preparation CL to use forward declaration only header in mojo's
generated code.
If we include forward declaration only header in mojo's generated code, we need
to include mojo header files in some places where definition is necessary.

master CL is in
https://chromium-review.googlesource.com/c/chromium/src/+/1438975

This CL was uploaded by git cl split.

R=kcwu@chromium.org

CC: rockot@google.com
Bug: 922875
Change-Id: Id3eab71f1c2635e3d449499975b1a93aff7bebcf
Reviewed-on: https://chromium-review.googlesource.com/c/1445869
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Commit-Queue: Kuang-che Wu <kcwu@chromium.org>
Reviewed-by: Kuang-che Wu <kcwu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#627718}

chrome/browser/chromeos/arc/video/gpu_arc_video_service_host.cc

@@ -18,6 +18,8 @@
 #include "components/arc/arc_bridge_service.h"
 #include "components/arc/arc_browser_context_keyed_service_factory_base.h"
 #include "components/arc/common/video_decode_accelerator.mojom.h"
+#include "components/arc/common/video_encode_accelerator.mojom.h"
+#include "components/arc/common/video_protected_buffer_allocator.mojom.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/gpu_service_registry.h"