Enable Oculus devices behind a runtime flag

This change moves the Oculus device to be behind a runtime flag, rather
than a build flag.  It will only be enabled if is_chrome_branding,
is_win, and src_internal is available.

The means that developers testing with Oculus support should still build
locally with enable_oculus_vr gn arg if they aren't building with chrome
branding.

Public bots (CQ) will not build this, but perftests/fyi will.

BUG=812050

Change-Id: I7b99d98b53adf8878c0523e2eafe4ab422936ebe
Reviewed-on: https://chromium-review.googlesource.com/917644
Reviewed-by: Dirk Pranke <[email protected]>
Reviewed-by: Brandon Jones <[email protected]>
Commit-Queue: Bill Orr <[email protected]>
Cr-Commit-Position: refs/heads/master@{#536817}
diff --git a/DEPS b/DEPS
index 823d5f7..f5836c6 100644
--- a/DEPS
+++ b/DEPS
@@ -58,7 +58,7 @@
   'checkout_libaom': True,
 
   # By default do not check out the Oculus SDK. Only available for Googlers.
-  'checkout_oculus_sdk' : False,
+  'checkout_oculus_sdk' : 'checkout_src_internal',
 
   # TODO(dpranke): change to != "small" once != is supported.
   'checkout_traffic_annotation_tools': 'checkout_configuration == "default"',