Cleanup: Remove unused fields related to Instant from sync protocol

This removes instant_url, search_terms_replacement_key, and
instant_url_post_params from SearchEngineSpecifics.

Bug: 476079
Change-Id: Ib0bed32ba21e11cc90e44234a6c321d97a02522b
Reviewed-on: https://chromium-review.googlesource.com/785910Reviewed-by: Nicolas Zea <zea@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519726}

components/sync/protocol/proto_visitors.h

@@ -715,15 +715,12 @@ VISIT_PROTO_FIELDS(const sync_pb::SearchEngineSpecifics& proto) {
   VISIT(suggestions_url);
   VISIT(prepopulate_id);
   VISIT(autogenerate_keyword);
-  VISIT(instant_url);
   VISIT(last_modified);
   VISIT(sync_guid);
   VISIT_REP(alternate_urls);
-  VISIT(search_terms_replacement_key);
   VISIT(image_url);
   VISIT(search_url_post_params);
   VISIT(suggestions_url_post_params);
-  VISIT(instant_url_post_params);
   VISIT(image_url_post_params);
   VISIT(new_tab_url);
 }

components/sync/protocol/search_engine_specifics.proto

@@ -7,6 +7,8 @@
 // Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
 // any fields in this file.
 
+// Fields that are not used anymore should be marked [deprecated = true].
+
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
@@ -51,20 +53,17 @@ message SearchEngineSpecifics {
   // notion no longer exists amongst synced search engines as we do not want to
   // sync managed search engines.
   // optional bool deprecated_created_by_policy = 14;
-  // The parameterized URL that is used for Instant results.
-  optional string instant_url = 15;
+  optional string instant_url = 15 [deprecated = true];
   // ID 16 reserved - previously used by |id|, now deprecated.
   // The last time this entry was modified by a user. A UTC timestamp with units
   // in microseconds.
   optional int64 last_modified = 17;
   // The primary identifier of this search engine entry for Sync.
   optional string sync_guid = 18;
-  // A list of URL patterns that can be used, in addition to |url| and
-  // |instant_url|, to extract search terms from a URL.
+  // A list of URL patterns that can be used, in addition to |url|, to extract
+  // search terms from a URL.
   repeated string alternate_urls = 19;
-  // Parameter that, if present in a search URL, indicates that Chrome should
-  // perform search terms replacement in the omnibox.
-  optional string search_terms_replacement_key = 20;
+  optional string search_terms_replacement_key = 20 [deprecated = true];
   // The parameterized URL that provides image results according to the image
   // content or image URL provided by user.
   optional string image_url = 21;
@@ -73,7 +72,7 @@ message SearchEngineSpecifics {
   // post parameters for the corresponding search URL.
   optional string search_url_post_params = 22;
   optional string suggestions_url_post_params = 23;
-  optional string instant_url_post_params = 24;
+  optional string instant_url_post_params = 24 [deprecated = true];
   optional string image_url_post_params = 25;
 
   // The parameterized URL for a search provider specified new tab page.