Add a Physical Web omnibox autocomplete provider

components/metrics/proto/omnibox_event.proto

Index: components/metrics/proto/omnibox_event.proto
diff --git a/components/metrics/proto/omnibox_event.proto b/components/metrics/proto/omnibox_event.proto
index 5d4f71996572cb7ab5846302be1f534db214e3b9..6fe15afb10dcdf4a3a75ef62797195eec23a1c74 100644
--- a/components/metrics/proto/omnibox_event.proto
+++ b/components/metrics/proto/omnibox_event.proto
@@ -168,6 +168,8 @@ message OmniboxEventProto {
     // a suggestion powered by a Chrome content provider.
     ON_DEVICE_CHROME = 13;
     CLIPBOARD_URL = 14;  // Suggestion coming from clipboard (iOS only).
+    PHYSICAL_WEB = 15;     // Suggestions triggered by URLs broadcast by nearby
+                           // devices (iOS only).
   }
 
   // The result set displayed on the completion popup
@@ -226,6 +228,9 @@ message OmniboxEventProto {
                                     // suggestions of any type.
       CALCULATOR              = 23; // A calculator answer.
       CLIPBOARD               = 24; // An URL based on the clipboard.
+      PHYSICAL_WEB            = 25; // A Physical Web nearby URL.
+      PHYSICAL_WEB_OVERFLOW   = 26; // An item representing multiple Physical
+                                    // Web nearby URLs.
     }
     optional ResultType result_type = 2;