Revert of Disable flaky test

chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc

Index: chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc b/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
index faed3cf741ba7b5936a255b75f60b6d8236a982b..c47ea93cf10e9715299975023f41e6d747d13543 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
@@ -456,9 +456,8 @@
   NavigateToURLAndCheckSubresources(GetURL(kHtmlDocumentWritePath));
 }
 
-// Disabled due to flakiness (crbug.com/673028).
-IN_PROC_BROWSER_TEST_F(ResourcePrefetchPredictorBrowserTest,
-                       DISABLED_LearningJavascriptAppendChild) {
+IN_PROC_BROWSER_TEST_F(ResourcePrefetchPredictorBrowserTest,
+                       LearningJavascriptAppendChild) {
   auto externalScript =
       AddExternalResource(GetURL(kScriptAppendChildPath),
                           content::RESOURCE_TYPE_SCRIPT, net::MEDIUM);