[Extensions Metrics] Record time spent on chrome://extensions page.

Records Extensions.Checkup.TimeSpent when the ExtensionsCheckup feature is disabled so that we can compare the behavior of the experiment and control groups.


Bug: 1034541
Change-Id: I58213193bc4d24ba1a2c832c69885fd62ed882e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2083744Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Archana Simha <archanasimha@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746914}

chrome/browser/ui/webui/extensions/extensions_ui.cc

@@ -399,8 +399,7 @@ ExtensionsUI::ExtensionsUI(content::WebUI* web_ui)
 }
 
 ExtensionsUI::~ExtensionsUI() {
-  if (timer_.has_value() &&
-      base::FeatureList::IsEnabled(extensions_features::kExtensionsCheckup))
+  if (timer_.has_value())
     UMA_HISTOGRAM_LONG_TIMES("Extensions.Checkup.TimeSpent", timer_->Elapsed());
 }