Bail out of resetting a URL's engagement if the URL is not valid.

chrome/browser/engagement/site_engagement_service.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/engagement/site_engagement_service.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <utility>
@@ skipping 487 matching lines @@
 
     double score =
         std::min(SiteEngagementScore::kMaxPoints,
                  (proportion_remaining * GetScore(origin)) + undecay);
     ResetScoreAndAccessTimesForURL(origin, score, &last_visit);
   }
 }
 
 void SiteEngagementService::ResetScoreAndAccessTimesForURL(
     const GURL& url, double score, const base::Time* updated_time) {
-  DCHECK(url.is_valid());
+  // It appears that the history service occassionally sends bad URLs to us.
+  // See crbug.com/612881.
+  if (!url.is_valid())
+    return;
+
   DCHECK_GE(score, 0);
   DCHECK_LE(score, SiteEngagementScore::kMaxPoints);
 
   HostContentSettingsMap* settings_map =
       HostContentSettingsMapFactory::GetForProfile(profile_);
   std::unique_ptr<base::DictionaryValue> score_dict =
       GetScoreDictForOrigin(settings_map, url);
   SiteEngagementScore engagement_score(clock_.get(), *score_dict);
 
   engagement_score.Reset(score, updated_time);
   if (score == 0) {
     settings_map->SetWebsiteSettingDefaultScope(
         url, GURL(), CONTENT_SETTINGS_TYPE_SITE_ENGAGEMENT, std::string(),
         nullptr);
     return;
   }
 
   if (engagement_score.UpdateScoreDict(score_dict.get())) {
     settings_map->SetWebsiteSettingDefaultScope(
         url, GURL(), CONTENT_SETTINGS_TYPE_SITE_ENGAGEMENT, std::string(),
         score_dict.release());
   }
 }