Enable the Site Characteristic Database by default

Bug: 839878
Change-Id: I045921f965486b19efc67a0a2628e2907936f501
Reviewed-on: https://chromium-review.googlesource.com/c/1277273
Commit-Queue: Sébastien Marchand <sebmarchand@chromium.org>
Reviewed-by: Chris Hamilton <chrisha@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606624}

chrome/browser/resource_coordinator/tab_manager_features.cc

@@ -35,7 +35,7 @@ const base::Feature kProactiveTabFreezeAndDiscard{
 
 // Enables the site characteristics database.
 const base::Feature kSiteCharacteristicsDatabase{
-    "SiteCharacteristicsDatabase", base::FEATURE_DISABLED_BY_DEFAULT};
+    "SiteCharacteristicsDatabase", base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Enables delaying the navigation of background tabs in order to improve
 // foreground tab's user experience.

testing/variations/fieldtrial_testing_config.json

@@ -4652,7 +4652,6 @@
                     "enable_features": [
                         "PageLifecycle",
                         "ProactiveTabFreezeAndDiscard",
-                        "SiteCharacteristicsDatabase",
                         "stop-non-timers-in-background"
                     ]
                 }