Add a Physical Web omnibox autocomplete provider

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 "components/omnibox/browser/autocomplete_input.h"
+#include "components/omnibox/browser/autocomplete_provider.h"
+
+class AutocompleteProviderClient;
+
+namespace base {
+class ListValue;
+}
+
+class PhysicalWebProvider : public AutocompleteProvider {
+public:
+  static PhysicalWebProvider* Create(AutocompleteProviderClient* client);
+
+  // AutocompleteProvider:
+  void Start(const AutocompleteInput& input, bool minimal_changes) override;
+  void Stop(bool clear_cached_results, bool due_to_user_inactivity) override;
+
+private:
+  PhysicalWebProvider(AutocompleteProviderClient* client);
+  ~PhysicalWebProvider() override;
+
+  // 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 slot is reserved for an

[Mark P, 2016/08/11 23:16:03]

nit: change "slot" back to "match" and "reserved" to "used"
(My comment made sense before you made ConstructMatches() call
AppendOverflowItem().  Before, when you called them sequentially in Start(),
ConstructMatches() really did leave one empty slot expecting
AppendOverflowItem() to fill it in.

[mattreynolds, 2016/08/16 20:35:25]

Done.

+  // overflow item.
+  void ConstructMatches(base::ListValue* metadata_list);
+
+  // Adds an overflow match item to |matches_| with a label indicating there are
+  // |additional_url_count| more nearby URLs. Selecting the overflow item
+  // navigates to the Physical Web WebUI, which displays the full list of nearby
+  // URLs.
+  void AppendOverflowItem(int additional_url_count);
+
+  AutocompleteProviderClient* client_;
+};
+
+#endif  // COMPONENTS_OMNIBOX_BROWSER_PHYSICAL_WEB_PROVIDER_H_