Small fixes for url_index_private_data.cc

components/omnibox/browser/url_index_private_data.cc

Index: components/omnibox/browser/url_index_private_data.cc
diff --git a/components/omnibox/browser/url_index_private_data.cc b/components/omnibox/browser/url_index_private_data.cc
index a702948211f91be9e6200e557d338118999c1ef8..87bdd3b50da8f397a1bbe36b1971c81d93344189 100644
--- a/components/omnibox/browser/url_index_private_data.cc
+++ b/components/omnibox/browser/url_index_private_data.cc
@@ -253,7 +253,7 @@ ScoredHistoryMatches URLIndexPrivateData::HistoryItemsForTerms(
     for (SearchTermCacheMap::iterator cache_iter = search_term_cache_.begin();
          cache_iter != search_term_cache_.end(); ) {
       if (!cache_iter->second.used_)
-        search_term_cache_.erase(cache_iter++);
+        cache_iter = search_term_cache_.erase(cache_iter);
       else
         ++cache_iter;
     }
@@ -497,6 +497,7 @@ URLIndexPrivateData::~URLIndexPrivateData() {}
 
 HistoryIDSet URLIndexPrivateData::HistoryIDSetFromWords(
     const String16Vector& unsorted_words) {
+  SCOPED_UMA_HISTOGRAM_TIMER("Omnibox.HistoryIDSetFromWords");

[Peter Kasting, 2016/11/30 21:39:50]

Double-checking: the existing omnibox provider time histograms are
insufficiently granular to measure HQP performance wins in the field?  (I want
to make sure you know about these histograms before adding this, since my own
knowledge of them is a little too sketchy to know whether this is good or not.)

   // Break the terms down into individual terms (words), get the candidate
   // set for each term, and intersect each to get a final candidate list.
   // Note that a single 'term' from the user's perspective might be
@@ -605,7 +606,7 @@ HistoryIDSet URLIndexPrivateData::HistoryIDsForTerm(
     for (WordIDSet::iterator word_set_iter = word_id_set.begin();
          word_set_iter != word_id_set.end(); ) {
       if (word_list_[*word_set_iter].find(term) == base::string16::npos)
-        word_id_set.erase(word_set_iter++);
+        word_set_iter = word_id_set.erase(word_set_iter);
       else
         ++word_set_iter;
     }