[Autofill] Turn off DOM Autocomplete suggestions by default.

Bug: 867893, 853940, 869912

Change-Id: Ia9a2729682dd8cbbc662562ab4ce9f79bfc1fbd2
Reviewed-on: https://chromium-review.googlesource.com/1158720Reviewed-by: Sebastien Seguin-Gagnon <sebsg@chromium.org>
Commit-Queue: Mathieu Perreault <mathp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579897}

components/autofill/core/common/autofill_features.cc

@@ -107,7 +107,7 @@ const base::Feature kAutofillSendOnlyCountryInGetUploadDetails{
 // types.
 const base::Feature kAutofillShowAutocompleteConsoleWarnings{
     "AutofillShowAutocompleteConsoleWarnings",
-    base::FEATURE_ENABLED_BY_DEFAULT};
+    base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Controls attaching the autofill type predictions to their respective
 // element in the DOM.