[omnibox] Fix match upgrade creating duplicate Pedal attachments

This CL prevents duplicate Pedal attachments from appearing in
omnibox suggestions as a result of match upgrades. It was
previously expected that duplicate matches, once buried, would
not be used or shown again, but that is not the case when entity
suggestions are involved.

Bug: 1122183
Change-Id: I4539d51304cf3a1acad87ecbf80c7c51749a2398
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2376722Reviewed-by: Tommy Li <tommycli@chromium.org>
Commit-Queue: Orin Jaworski <orinj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#802026}

components/omnibox/browser/autocomplete_match.cc

@@ -1104,7 +1104,7 @@ size_t AutocompleteMatch::EstimateMemoryUsage() const {
 }
 
 void AutocompleteMatch::UpgradeMatchWithPropertiesFrom(
-    const AutocompleteMatch& duplicate_match) {
+    AutocompleteMatch& duplicate_match) {
   // For Entity Matches, absorb the duplicate match's |allowed_to_be_default|
   // and |inline_autocomplete| properties.
   if (type == AutocompleteMatchType::SEARCH_SUGGEST_ENTITY &&
@@ -1136,6 +1136,7 @@ void AutocompleteMatch::UpgradeMatchWithPropertiesFrom(
   // Take the |pedal|, if any, so that it will be presented instead of buried.
   if (!pedal && duplicate_match.pedal) {
     pedal = duplicate_match.pedal;
+    duplicate_match.pedal = nullptr;
   }
 }
 

components/omnibox/browser/autocomplete_match.h

@@ -423,7 +423,7 @@ struct AutocompleteMatch {
   // Upgrades this match by absorbing the best properties from
   // |duplicate_match|. For instance: if |duplicate_match| has a higher
   // relevance score, this match's own relevance score will be upgraded.
-  void UpgradeMatchWithPropertiesFrom(const AutocompleteMatch& duplicate_match);
+  void UpgradeMatchWithPropertiesFrom(AutocompleteMatch& duplicate_match);
 
   // Called for navigation suggestions whose URLs cannot be inline autocompleted
   // (e.g. because the input is not a prefix of the URL), to check if |title|