Telemetry: add a metadata layer between page set and .wpr.

tools/telemetry/telemetry/multi_page_benchmark_unittest.py

Index: tools/telemetry/telemetry/multi_page_benchmark_unittest.py
diff --git a/tools/telemetry/telemetry/multi_page_benchmark_unittest.py b/tools/telemetry/telemetry/multi_page_benchmark_unittest.py
index 14e8d4fb592e0502400fc405eb8d9c47f1147448..20921e940bbbe2c0d81a7da03aec3b9025ba35fc 100644
--- a/tools/telemetry/telemetry/multi_page_benchmark_unittest.py
+++ b/tools/telemetry/telemetry/multi_page_benchmark_unittest.py
@@ -85,13 +85,13 @@ class MultiPageBenchmarkUnitTest(
     test_archive = '/tmp/google.wpr'
     try:
       ps = page_set.PageSet()
-      ps.archive_path = test_archive
       benchmark = BenchForReplay()
 
       # First record an archive with only www.google.com.
       self._options.wpr_mode = wpr_modes.WPR_RECORD
 
       ps.pages = [page_module.Page('http://www.google.com/')]
+      ps.pages[0].archive_path = test_archive
       all_results = self.RunBenchmark(benchmark, ps, options=self._options)
       self.assertEquals(0, len(all_results.page_failures))
 
@@ -99,10 +99,12 @@ class MultiPageBenchmarkUnitTest(
       self._options.wpr_mode = wpr_modes.WPR_REPLAY
 
       ps.pages = [page_module.Page('http://www.foo.com/')]
+      ps.pages[0].archive_path = test_archive
       all_results = self.RunBenchmark(benchmark, ps, options=self._options)
       self.assertEquals(1, len(all_results.page_failures))
 
       ps.pages = [page_module.Page('http://www.google.com/')]
+      ps.pages[0].archive_path = test_archive
       all_results = self.RunBenchmark(benchmark, ps, options=self._options)
       self.assertEquals(0, len(all_results.page_failures))