Add UMA metric to track usage of sending a mousedown to select elements.

third_party/WebKit/LayoutTests/imported/wpt/html/semantics/grouping-content/the-ol-element/grouping-ol-start-reftest-002-expected.html

Index: third_party/WebKit/LayoutTests/imported/wpt/html/semantics/grouping-content/the-ol-element/grouping-ol-start-reftest-002-expected.html
diff --git a/third_party/WebKit/LayoutTests/imported/wpt/html/semantics/grouping-content/the-ol-element/grouping-ol-start-reftest-002-expected.html b/third_party/WebKit/LayoutTests/imported/wpt/html/semantics/grouping-content/the-ol-element/grouping-ol-start-reftest-002-expected.html
index e40c12c3a2fd9717bcae84a0c256d252e0d7acc8..2ba4af9b100c61ddac0dd6ea5f4f311cb03465cf 100644
--- a/third_party/WebKit/LayoutTests/imported/wpt/html/semantics/grouping-content/the-ol-element/grouping-ol-start-reftest-002-expected.html
+++ b/third_party/WebKit/LayoutTests/imported/wpt/html/semantics/grouping-content/the-ol-element/grouping-ol-start-reftest-002-expected.html
@@ -5,7 +5,6 @@
     <title>ol element</title>
     <link rel="author" title="dzenana" href="mailto:dzenana.trenutak@gmail.com">
     <link rel="help" href="https://html.spec.whatwg.org/multipage/#the-ol-element">
-    <link rel="match" href="grouping-ol-start-reftest-002.html" />
     <meta name="assert" content="Sequences produced by calculated values for LI elements within OL match spec's expectations. (part two)" />
     <style type="text/css">
         span p {display:list-item; margin-left: 0; margin-top: 0; margin-bottom: 0; padding-left: 0; padding-top: 0; padding-bottom: 0;}