[System Health] Reenable tests failing due to bug in ScrollToElement

tools/perf/page_sets/system_health/browsing_stories.py

Index: tools/perf/page_sets/system_health/browsing_stories.py
diff --git a/tools/perf/page_sets/system_health/browsing_stories.py b/tools/perf/page_sets/system_health/browsing_stories.py
index 8cbc0cc8b905865eea14a89fd0b9de45de053da8..2c93aa34bdb6a5bb2fe2f007b2169ee876042783 100644
--- a/tools/perf/page_sets/system_health/browsing_stories.py
+++ b/tools/perf/page_sets/system_health/browsing_stories.py
@@ -96,7 +96,6 @@ class CnnStory(_NewsBrowsingStory):
   ITEMS_TO_VISIT = 2
 
 
-@decorators.Disabled('android')  # crbug.com/664518
 class FacebookMobileStory(_NewsBrowsingStory):
   NAME = 'browse:social:facebook'
   URL = 'https://www.facebook.com/rihanna'
@@ -258,7 +257,6 @@ class _MediaBrowsingStory(_BrowsingStory):
     action_runner.Wait(self.ITEM_VIEW_TIME_IN_SECONDS)
 
 
-@decorators.Disabled('android')  # crbug.com/664518
 class ImgurMobileStory(_MediaBrowsingStory):
   NAME = 'browse:media:imgur'
   URL = 'http://imgur.com/gallery/5UlBN'