Avoid DCHECK failure for chrome:// URLs in autocomplete suggestions

components/omnibox/browser/autocomplete_result.cc

Index: components/omnibox/browser/autocomplete_result.cc
diff --git a/components/omnibox/browser/autocomplete_result.cc b/components/omnibox/browser/autocomplete_result.cc
index 14f084337e980300abdaf7d6df4ba3b249b8374d..9aa9815358303c2b6d6aeef42b3c658805c943e1 100644
--- a/components/omnibox/browser/autocomplete_result.cc
+++ b/components/omnibox/browser/autocomplete_result.cc
@@ -166,11 +166,20 @@ void AutocompleteResult::SortAndCull(
             : base::string16()) +
         base::ASCIIToUTF16(", input=") +
         input.text();
-    DCHECK(default_match_->allowed_to_be_default_match) << debug_info;
-    // If the default match is valid (i.e., not a prompt/placeholder), make
-    // sure the type of destination is what the user would expect given the
-    // input.
-    if (default_match_->destination_url.is_valid()) {
+
+    // We should only get here with an empty omnibox for automatic suggestions
+    // on focus on the NTP; in these cases hitting enter should do nothing, so
+    // there should be no default match.  Otherwise, we're doing automatic
+    // suggestions for the currently visible URL (and hitting enter should
+    // reload it), or the user is typing; in either of these cases, there should
+    // be a default match.
+    DCHECK_NE(input.text().empty(), default_match_->allowed_to_be_default_match)
+        << debug_info;
+
+    // For navigable default matches, make sure the destination type is what the
+    // user would expect given the input.
+    if (default_match_->allowed_to_be_default_match &&
+        default_match_->destination_url.is_valid()) {
       if (AutocompleteMatch::IsSearchType(default_match_->type)) {
         // We shouldn't get query matches for URL inputs.
         DCHECK_NE(metrics::OmniboxInputType::URL, input.type()) << debug_info;