Add HidService mojom and stub implementation

HidService will be used to provide access to devices enumerated
by the HID backend without exposing unnecessary device details to
the render process.

BUG=890096

Change-Id: I73016f1091ff8744359afb57241eabaf28fdef9b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1636680
Commit-Queue: Matt Reynolds <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Reviewed-by: John Abd-El-Malek <[email protected]>
Cr-Commit-Position: refs/heads/master@{#667772}
diff --git a/content/browser/BUILD.gn b/content/browser/BUILD.gn
index e336736..a00d400 100644
--- a/content/browser/BUILD.gn
+++ b/content/browser/BUILD.gn
@@ -992,6 +992,8 @@
     "gpu/gpu_process_host.h",
     "gpu/shader_cache_factory.cc",
     "gpu/shader_cache_factory.h",
+    "hid/hid_service.cc",
+    "hid/hid_service.h",
     "histogram_controller.cc",
     "histogram_controller.h",
     "histogram_subscriber.h",