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

third_party/WebKit/LayoutTests/imported/wpt/custom-elements/custom-element-registry/define.html

Index: third_party/WebKit/LayoutTests/imported/wpt/custom-elements/custom-element-registry/define.html
diff --git a/third_party/WebKit/LayoutTests/imported/wpt/custom-elements/custom-elements-registry/define.html b/third_party/WebKit/LayoutTests/imported/wpt/custom-elements/custom-element-registry/define.html
similarity index 98%
rename from third_party/WebKit/LayoutTests/imported/wpt/custom-elements/custom-elements-registry/define.html
rename to third_party/WebKit/LayoutTests/imported/wpt/custom-elements/custom-element-registry/define.html
index e04df1fea6749da61e188216407a484b530b177b..fedb687416e8bea53e83a3c7cf46f862f660672e 100644
--- a/third_party/WebKit/LayoutTests/imported/wpt/custom-elements/custom-elements-registry/define.html
+++ b/third_party/WebKit/LayoutTests/imported/wpt/custom-elements/custom-element-registry/define.html
@@ -110,7 +110,7 @@
     }, `Element names: defining an element named ${name} should throw a SyntaxError`);
   });
 
-  // 3. If this CustomElementsRegistry contains an entry with name name,
+  // 3. If this CustomElementRegistry contains an entry with name name,
   // then throw a NotSupportedError and abort these steps.
   test(() =>  {
     customElements.define('test-define-dup-name', class {});
@@ -119,7 +119,7 @@
     });
   }, 'If the name is already defined, should throw a NotSupportedError');
 
-  // 5. If this CustomElementsRegistry contains an entry with constructor constructor,
+  // 5. If this CustomElementRegistry contains an entry with constructor constructor,
   // then throw a NotSupportedError and abort these steps.
   test(() =>  {
     class TestDupConstructor {};