[ar] Make enable_arcore depend on enable_vr

This is currently required (eg, because we depend on mailbox to surface
bridge).

Bug: 861866
Change-Id: Ie9d6a76a2f19d8645d25463d64c338f40554e56b
Reviewed-on: https://chromium-review.googlesource.com/1132392
Reviewed-by: Bill Orr <billorr@chromium.org>
Commit-Queue: Ian Vollick <vollick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574011}

device/vr/buildflags/buildflags.gni

@@ -30,18 +30,24 @@ declare_args() {
 
   # Whether to include VR extras like test APKs in non-VR-specific targets
   include_vr_data = false
+}
 
+declare_args() {
   # TODO(crbug.com/837999, crbug.com/841389): We currently only support arm and
   # we are limiting to canary and dev until binary size issues are resolved.
-  # TODO(crbug.com/845080): add android_channel == "dev" || "canary"
-  package_arcore = is_android && !is_chromecast && current_cpu == "arm" &&
-                   (android_channel == "default" ||
-                    android_channel == "canary" || android_channel == "dev")
+  # TODO(crbug.com/836524): once we've refactored AR code out from vr
+  # directories, we can stop requiring |enable_vr| here.
+  package_arcore =
+      enable_vr && is_android && !is_chromecast && current_cpu == "arm" &&
+      (android_channel == "default" || android_channel == "canary" ||
+       android_channel == "dev")
 
   # TODO(crbug.com/841389): We should eventually have a single flag for
   # enabling arcore, but we currently don't support ARCore in 64bit, and we do
   # not support all channels. This flag governs the inclusion of code that must
   # be identical across configs.
-  enable_arcore = is_android && !is_chromecast &&
+  # TODO(crbug.com/836524): once we've refactored AR code out from vr
+  # directories, we can stop requiring |enable_vr| here.
+  enable_arcore = enable_vr && is_android && !is_chromecast &&
                   (current_cpu == "arm" || current_cpu == "arm64")
 }