Show Physical Web zero-suggest omnibox suggestions after query is deleted

components/omnibox/browser/physical_web_provider.cc

 // Copyright (c) 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/omnibox/browser/physical_web_provider.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 57 matching lines @@
   }
 
   physical_web::PhysicalWebDataSource* data_source =
       client_->GetPhysicalWebDataSource();
   if (!data_source) {
     done_ = true;
     nearby_url_count_ = 0;
     return;
   }
 
-  if (input.from_omnibox_focus()) {
+  const bool input_from_focus = input.from_omnibox_focus();
+  const bool empty_input_from_user = !input_from_focus && input.text().empty();
+
+  if (input_from_focus || empty_input_from_user) {
     ConstructZeroSuggestMatches(data_source->GetMetadataList());
 
     if (!matches_.empty()) {
       had_physical_web_suggestions_ = true;
       had_physical_web_suggestions_at_focus_or_later_ = true;
     }
 
-    if (!zero_suggest_enabled_) {
+    // Don't show zero-suggest suggestions unless the PhysicalWebZeroSuggest
+    // omnibox experiment parameter is enabled. If the omnibox input is empty
+    // because the user cleared it, also require that PhysicalWebAfterTyping is
+    // enabled.
+    if (!zero_suggest_enabled_ ||
+        (empty_input_from_user && !after_typing_enabled_)) {
       matches_.clear();
     }
 
     // In zero-suggest, Physical Web matches should never be default. If the
     // omnibox input is non-empty and we have at least one Physical Web match,
     // add the current URL as the default so that hitting enter after focusing
     // the omnibox causes the current page to reload. If the input field is
     // empty, no default match is required.
     if (!matches_.empty() && !input.text().empty()) {
       matches_.push_back(VerbatimMatchForURL(
           client_, input, input.current_url(), history_url_provider_, -1));
     }
   } else {
     ConstructQuerySuggestMatches(data_source->GetMetadataList(), input);
 
     if (!matches_.empty()) {
       had_physical_web_suggestions_ = true;
       had_physical_web_suggestions_at_focus_or_later_ = true;
     }
 
+    // Don't show Physical Web suggestions after the user starts typing unless
+    // the PhysicalWebAfterTyping omnibox experiment parameter is enabled.
     if (!after_typing_enabled_) {
       matches_.clear();
     }
   }
 
   done_ = true;
 }
 
 void PhysicalWebProvider::Stop(bool clear_cached_results,
                                bool due_to_user_inactivity) {
@@ skipping 156 matching lines @@
       AutocompleteInput::FormattedStringWithEquivalentMeaning(
           url, match.contents, client_->GetSchemeClassifier());
 
   match.description =
       l10n_util::GetStringUTF16(IDS_PHYSICAL_WEB_OVERFLOW_DESCRIPTION);
   match.description_class.push_back(
       ACMatchClassification(0, ACMatchClassification::NONE));
 
   matches_.push_back(match);
 }