Roll WebXR samples repo revision

Rolls the WebXR samples repo DEPS revision to the most recent commit,
which should have all the fixes necessary to get the XR perf tests
running again.

Bug: 853400
Change-Id: I2327ca1c83cee3f242a0b9cdfb72b14fca09751c
Reviewed-on: https://chromium-review.googlesource.com/1113912Reviewed-by: Brandon Jones <bajones@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570124}

DEPS

@@ -260,7 +260,7 @@ deps = {
     Var('chromium_git') + '/external/github.com/toji/webvr.info.git' + '@' + 'c58ae99b9ff9e2aa4c524633519570bf33536248',
 
   'src/chrome/test/data/vr/webxr_samples':
-    Var('chromium_git') + '/external/github.com/immersive-web/webxr-samples.git' + '@' + '1848aed8fc333030c26787658db8fa4261a2b955',
+    Var('chromium_git') + '/external/github.com/immersive-web/webxr-samples.git' + '@' + '18652a69be2092f2c35a3f91213abc8b80dd3f25',
 
   'src/ios/third_party/earl_grey/src': {
       'url': Var('chromium_git') + '/external/github.com/google/EarlGrey.git' + '@' + '91c27bb8a15e723df974f620f7f576a30a6a7484',