Ensure nearby URL count metric is properly initialized

components/omnibox/browser/physical_web_provider.h

 // 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.
 
 #ifndef COMPONENTS_OMNIBOX_BROWSER_PHYSICAL_WEB_PROVIDER_H_
 #define COMPONENTS_OMNIBOX_BROWSER_PHYSICAL_WEB_PROVIDER_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 29 matching lines @@
   // AutocompleteProvider:
   void Start(const AutocompleteInput& input, bool minimal_changes) override;
   void Stop(bool clear_cached_results, bool due_to_user_inactivity) override;
   void AddProviderInfo(ProvidersInfo* provider_info) const override;
 
  private:
   PhysicalWebProvider(AutocompleteProviderClient* client,
                       HistoryURLProvider* history_url_provider);
   ~PhysicalWebProvider() override;
 
+  // Called when a new omnibox session is started. For the purposes of this
+  // provider, a session begins when the omnibox is initially focused.
+  void BeginOmniboxSession();
+
   // When the user has focused the omnibox but not yet entered any text (i.e.,
   // the Zero Suggest case), calling this method adds a separate match item to
   // |matches_| for each nearby URL in |metadata_list|, up to the maximum number
   // of matches allowed. If the total number of nearby URLs exceeds this limit,
   // one match is used for an overflow item.
   void ConstructZeroSuggestMatches(
       std::unique_ptr<physical_web::MetadataList> metadata_list);
 
   // When the user has entered text into the omnibox (i.e., the Query Suggest
   // case), calling this method adds a separate match item to |matches_| for
@@ skipping 15 matching lines @@
 
   AutocompleteProviderClient* client_;
 
   // Used for efficiency when creating the verbatim match. Can be null.
   HistoryURLProvider* history_url_provider_;
 
   // The number of nearby Physical Web URLs when the provider last constructed
   // matches.
   size_t nearby_url_count_;
 
+  // The number of nearby Physical Web URLs when the omnibox input was last
+  // focused.
+  size_t nearby_url_count_at_focus_;

[Mark P, 2017/02/22 06:25:39]

Can you use npos and test for it explicitly rather than having a second field to
detect validity?

[mattreynolds, 2017/02/22 20:53:55]

Sure, done.

+
+  // The nearby URL count is invalid if the omnibox was not focused during the
+  // current omnibox session. Invalid URL counts should not be recorded.
+  bool nearby_url_count_at_focus_valid_;
+
   // If true, provide suggestions when the user has focused the omnibox but has
   // not typed anything.
   bool zero_suggest_enabled_;
 
   // If true, provide suggestions when the user has entered a query into the
   // omnibox.
   bool after_typing_enabled_;
 
   // The base relevance score for Physical Web URL suggestions when the user has
   // not typed anything into the omnibox.
@@ skipping 10 matching lines @@
 
   // Set to true if at least one suggestion was created since the last time the
   // omnibox was focused, even if the suggestion could not be displayed due to
   // a field trial.
   bool had_physical_web_suggestions_at_focus_or_later_;
 
   DISALLOW_COPY_AND_ASSIGN(PhysicalWebProvider);
 };
 
 #endif  // COMPONENTS_OMNIBOX_BROWSER_PHYSICAL_WEB_PROVIDER_H_