Mark SpatialNavigation.Advance metric obsolete

UMA isn't enabled on most devices that use spatial navigation and no one
is actively looking at this so let it expire in M85.

Bug: 1088658
Change-Id: I4aa10d3fd2cb1d9b6dc6d7318c3a1bbfe605bd21
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2443498Reviewed-by: Brian White <bcwhite@chromium.org>
Reviewed-by: Liviu Tinta <liviutinta@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815660}

third_party/blink/renderer/core/page/spatial_navigation_controller.cc

@@ -31,7 +31,6 @@
 #include "third_party/blink/renderer/core/page/page.h"
 #include "third_party/blink/renderer/core/page/spatial_navigation.h"
 #include "third_party/blink/renderer/platform/geometry/layout_rect.h"
-#include "third_party/blink/renderer/platform/instrumentation/histogram.h"
 
 #include "third_party/blink/renderer/core/css/style_change_reason.h"
 
@@ -294,8 +293,6 @@ void SpatialNavigationController::Trace(Visitor* visitor) const {
 
 bool SpatialNavigationController::Advance(
     SpatialNavigationDirection direction) {
-  SCOPED_BLINK_UMA_HISTOGRAM_TIMER("Blink.SpatialNavigation.Advance");
-
   Node* interest_node = StartingNode();
   if (!interest_node)
     return false;

tools/metrics/histograms/histograms_xml/blink/histograms.xml

@@ -1789,6 +1789,9 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 
 <histogram name="Blink.SpatialNavigation.Advance" units="microseconds"
     expires_after="M85">
+  <obsolete>
+    Expired in M85.
+  </obsolete>
   <owner>bokan@chromium.org</owner>
   <summary>
     Time it takes to find best candidate element, set focus or scroll for given