telemetry: Fixed summary of by_url results when page-repeat>1

tools/telemetry/telemetry/page/buildbot_page_measurement_results.py

Index: tools/telemetry/telemetry/page/buildbot_page_measurement_results.py
diff --git a/tools/telemetry/telemetry/page/buildbot_page_measurement_results.py b/tools/telemetry/telemetry/page/buildbot_page_measurement_results.py
index c086eff4a142444cfcf74f93fbe7760fd907a173..0f1ab814546bc3a91e51c7d18c37c98040943cd4 100644
--- a/tools/telemetry/telemetry/page/buildbot_page_measurement_results.py
+++ b/tools/telemetry/telemetry/page/buildbot_page_measurement_results.py
@@ -33,12 +33,16 @@ class BuildbotPageMeasurementResults(
       success_page_results = self._page_results
 
     # Print out the list of unique pages.
+    # Use a set and a list to efficiently create an order preserving list of
+    # unique URLs.
     unique_page_urls = []
+    unique_page_urls_set = set()
     for page_values in success_page_results:
       url = page_values.page.display_url
-      if unique_page_urls and unique_page_urls[0] == url:
-        break
+      if url in unique_page_urls_set:
+        continue
       unique_page_urls.append(url)
+      unique_page_urls_set.add(url)
     perf_tests_helper.PrintPages(unique_page_urls)
 
     # Build the results summary.