Revert of Revert of Flip extension background page throttling on by default

extensions/browser/extension_host.cc

Index: extensions/browser/extension_host.cc
diff --git a/extensions/browser/extension_host.cc b/extensions/browser/extension_host.cc
index 0afeb4338c865c058fe79e77f80c98d5dc39e069..edeb7461878b652ba798e6e166b0ba565816cf5a 100644
--- a/extensions/browser/extension_host.cc
+++ b/extensions/browser/extension_host.cc
@@ -153,12 +153,9 @@
             "464206 ExtensionHost::CreateRenderViewNow2"));
     DCHECK(IsRenderViewLive());
     if (extension_) {
-      std::string group_name = base::FieldTrialList::FindFullName(
-          "ThrottleExtensionBackgroundPages");
-      if ((group_name == "ThrottlePersistent" &&
-           extensions::BackgroundInfo::HasPersistentBackgroundPage(
-               extension_)) ||
-          group_name == "ThrottleAll") {
+      if (extensions::BackgroundInfo::HasPersistentBackgroundPage(extension_) &&
+          base::FieldTrialList::FindFullName(
+              "ThrottleExtensionBackgroundPages") != "Disabled") {
         host_contents_->WasHidden();
       }
     }