Disable Billing interstitial by default since WebView support isn't ready

R=drubery

Bug: 867518,890484, 887186
Change-Id: I1e5a8c342deef6737f6c69d99ede839028d9aae9
Reviewed-on: https://chromium-review.googlesource.com/c/1356124
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612482}

components/safe_browsing/features.cc

@@ -24,7 +24,7 @@ const base::Feature kAdSamplerTriggerFeature{"SafeBrowsingAdSamplerTrigger",
 
 // Controls the billing interstitial UI.
 const base::Feature kBillingInterstitial{"BillingInterstitial",
-                                         base::FEATURE_ENABLED_BY_DEFAULT};
+                                         base::FEATURE_DISABLED_BY_DEFAULT};
 
 // If enabled in pre-network-service world, SafeBrowsing URL checks are done by
 // applying SafeBrowsing's URLLoaderThrottle subclasses to ThrottlingURLLoader.