Don't log chrome ext. pages on site visit timeouts

It doesn't seem interesting to know that the browser failed
to even navigate away from the extension page (that we
already had open, I assume).

crawler.py

@@ -1001,18 +1001,12 @@ def get_current_url(self):
         except Exception:
             return None
 
-    def crawl(self):
+    def crawl(self, domains):
         """
         Visit the top `num_sites` websites in the Tranco list, in order, in
         a virtual browser with Privacy Badger installed. Afterwards, save the
         action_map and snitch_map that the Badger learned.
         """
-
-        if self.num_sites == 0:
-            domains = []
-        else:
-            domains = self.get_sitelist()
-
         num_visited = 0
         old_snitches = self.dump_data()['snitch_map']
 
@@ -1037,23 +1031,25 @@ def crawl(self):
                 self.logger.info("Visiting %d: %s", i + 1, domain)
                 self.visit_domain(domain)
 
-                curl_or_domain = self.get_current_url() or domain
-                if curl_or_domain.startswith(CHROME_URL_PREFIX):
+                curl = self.get_current_url()
+                if curl and curl.startswith(CHROME_URL_PREFIX):
                     self.logger.error("Error loading %s: "
-                        "driver.current_url is still %s",
-                        domain, curl_or_domain)
+                        "driver.current_url is still a %s page",
+                        domain, CHROME_URL_PREFIX)
                     continue
 
-                self.logger.info("Visited %s", curl_or_domain)
+                self.logger.info("Visited %s", curl or domain)
                 num_visited += 1
 
             except (MaxRetryError, ProtocolError, ReadTimeoutError) as ex:
                 self.logger.error("Error loading %s:\n%s", domain, str(ex))
                 self.restart_browser()
 
             except TimeoutException:
-                self.logger.warning("Timed out loading %s",
-                                    self.get_current_url() or domain)
+                curl = self.get_current_url()
+                if curl and curl.startswith(CHROME_URL_PREFIX):
+                    curl = None
+                self.logger.warning("Timed out loading %s", curl or domain)
 
             except WebDriverException as ex:
                 if should_restart(ex):
@@ -1199,4 +1195,9 @@ def save(self, data, name='results.json'):
                 data = json.load(f)
                 crawler.load_user_data(data)
 
-        crawler.crawl()
+        if crawler.num_sites == 0:
+            domains = []
+        else:
+            domains = crawler.get_sitelist()
+
+        crawler.crawl(domains)