Telemetry: featurize tab_switching test for compressed swap performance

tools/telemetry/telemetry/page/page_runner.py

Index: tools/telemetry/telemetry/page/page_runner.py
diff --git a/tools/telemetry/telemetry/page/page_runner.py b/tools/telemetry/telemetry/page/page_runner.py
index d70d3e73052a8afe2b6b89cbaf8c90c52cc955bd..d0bc1d677e06f14eec8144226e73954f25e3ed1e 100644
--- a/tools/telemetry/telemetry/page/page_runner.py
+++ b/tools/telemetry/telemetry/page/page_runner.py
@@ -208,6 +208,13 @@ def AddCommandLineArgs(parser):
                    help='Maximum number of test failures before aborting '
                    'the run. Defaults to the number specified by the '
                    'PageTest.')
+  group.add_option('--pageset-replicate', default=1, type='int',

[tonyg, 2014/09/29 16:54:09]

It's not clear from this description why this is different from
--pageset-repeat. Perhaps we should just change the behavior of the tab
switching measurement given a pageset repeat? Or perhaps we should just make a
new page set for the case you have in mind?

[aiolos (Not reviewing), 2015/04/03 18:16:39]

It's also unclear to me why this is different.

+                   help='Number of times the page set should be replicated '
+                   '(for multi-tab tests).  Defaults to 1')
+  group.add_option('--pageset-truncate', default=sys.maxint, type='int',

[aiolos (Not reviewing), 2015/04/03 18:16:39]

This logic shouldn't be here if it's needed and I'm not convinced it's needed.
Why can't you just create the page_set of the size you need?

+                   help='Maximum size of page set after replication (for '
+                   'multi-tab tests).  Defaults to MAXINT and has no effect '
+                   'if larger than the size of the replicated page set.')
   parser.add_option_group(group)
 
   # WPR options
@@ -370,6 +377,12 @@ def Run(test, page_set, expectations, finder_options, results):
     possible_browser.RunRemote()
     sys.exit(0)
 
+  # Replicate page set as requested.
+  page_set.pages *= finder_options.pageset_replicate
+
+  # Truncate the page set to the given number of pages.
+  page_set.pages = page_set.pages[:finder_options.pageset_truncate]
+
   # Reorder page set based on options.
   pages = _ShuffleAndFilterPageSet(page_set, finder_options)