Misc. omnibox cleanup:

components/omnibox/browser/history_url_provider.cc

Index: components/omnibox/browser/history_url_provider.cc
diff --git a/components/omnibox/browser/history_url_provider.cc b/components/omnibox/browser/history_url_provider.cc
index 9747452afa24a387d48f670458bb1a8010500ed1..a3cdf351267f7b525b5b2dffbf84bd218331551d 100644
--- a/components/omnibox/browser/history_url_provider.cc
+++ b/components/omnibox/browser/history_url_provider.cc
@@ -127,7 +127,8 @@ double CalculateRelevanceUsingScoreBuckets(
   if (decayed_count > 0)
     decayed_count *= decay_factor;
 
-  const HUPScoringParams::ScoreBuckets::CountMaxRelevance* score_bucket = NULL;
+  const HUPScoringParams::ScoreBuckets::CountMaxRelevance* score_bucket =
+      nullptr;
   const double factor = (score_buckets.use_decay_factor() ?
       decay_factor : decayed_count);
   for (size_t i = 0; i < score_buckets.buckets().size(); ++i) {
@@ -434,7 +435,7 @@ HistoryURLProviderParams::HistoryURLProviderParams(
       exact_suggestion_is_in_history(false),
       promote_type(NEITHER),
       default_search_provider(default_search_provider ?
-          new TemplateURL(default_search_provider->data()) : NULL),
+          new TemplateURL(default_search_provider->data()) : nullptr),
       search_terms_data(new SearchTermsDataSnapshot(search_terms_data)) {
 }
 
@@ -445,7 +446,7 @@ HistoryURLProvider::HistoryURLProvider(AutocompleteProviderClient* client,
                                        AutocompleteProviderListener* listener)
     : HistoryProvider(AutocompleteProvider::TYPE_HISTORY_URL, client),
       listener_(listener),
-      params_(NULL),
+      params_(nullptr),
       search_url_database_(OmniboxFieldTrial::HUPSearchDatabase()) {
   // Initialize the default HUP scoring params.
   OmniboxFieldTrial::GetDefaultHUPScoringParams(&scoring_params_);
@@ -505,10 +506,10 @@ void HistoryURLProvider::Start(const AutocompleteInput& input,
 
   // Get the default search provider and search terms data now since we have to
   // retrieve these on the UI thread, and the second pass runs on the history
-  // thread. |template_url_service| can be NULL when testing.
+  // thread. |template_url_service| can be null when testing.
   TemplateURLService* template_url_service = client()->GetTemplateURLService();
   TemplateURL* default_search_provider = template_url_service ?
-      template_url_service->GetDefaultSearchProvider() : NULL;
+      template_url_service->GetDefaultSearchProvider() : nullptr;
 
   // Create the data structure for the autocomplete passes.  We'll save this off
   // onto the |params_| member for later deletion below if we need to run pass
@@ -523,15 +524,14 @@ void HistoryURLProvider::Start(const AutocompleteInput& input,
   // Pass 1: Get the in-memory URL database, and use it to find and promote
   // the inline autocomplete match, if any.
   history::URLDatabase* url_db = history_service->InMemoryDatabase();
-  // url_db can be NULL if it hasn't finished initializing (or failed to
-  // initialize).  In this case all we can do is fall back on the second
-  // pass.
+  // url_db can be null if it hasn't finished initializing (or failed to
+  // initialize).  In this case all we can do is fall back on the second pass.
   //
   // TODO(pkasting): We should just block here until this loads.  Any time
   // someone unloads the history backend, we'll get inconsistent inline
   // autocomplete behavior here.
   if (url_db) {
-    DoAutocomplete(NULL, url_db, params.get());
+    DoAutocomplete(nullptr, url_db, params.get());
     matches_.clear();
     PromoteMatchesIfNecessary(*params);
     // NOTE: We don't reset |params| here since at least the |promote_type|
@@ -601,10 +601,10 @@ AutocompleteMatch HistoryURLProvider::SuggestExactInput(
     const URLPrefix* best_prefix = URLPrefix::BestURLPrefix(
         base::UTF8ToUTF16(destination_url.spec()), input.text());
     // It's possible for match.destination_url to not contain the user's input
-    // at all (so |best_prefix| is NULL), for example if the input is
+    // at all (so |best_prefix| is null), for example if the input is
     // "view-source:x" and |destination_url| has an inserted "http://" in the
     // middle.
-    if (best_prefix == NULL) {
+    if (!best_prefix) {
       AutocompleteMatch::ClassifyMatchInString(input.text(),
                                                match.contents,
                                                ACMatchClassification::URL,
@@ -623,7 +623,7 @@ AutocompleteMatch HistoryURLProvider::SuggestExactInput(
 void HistoryURLProvider::ExecuteWithDB(HistoryURLProviderParams* params,
                                        history::HistoryBackend* backend,
                                        history::URLDatabase* db) {
-  // We may get called with a NULL database if it couldn't be properly
+  // We may get called with a null database if it couldn't be properly
   // initialized.
   if (!db) {
     params->failed = true;
@@ -846,7 +846,7 @@ void HistoryURLProvider::QueryComplete(
   // If the user hasn't already started another query, clear our member pointer
   // so we can't write into deleted memory.
   if (params_ == params_gets_deleted)
-    params_ = NULL;
+    params_ = nullptr;
 
   // Don't send responses for queries that have been canceled.
   if (params->cancel_flag.IsSet())