[telemetry] Cleanups for benchmarks importing page sets.

tools/perf/benchmarks/memory.py

Index: tools/perf/benchmarks/memory.py
diff --git a/tools/perf/benchmarks/memory.py b/tools/perf/benchmarks/memory.py
index 826e6f1ff348a3a5217012cf4311a4268a8ce0ac..fa2402ffb591a2774b340d1a84f296c8295c6bdd 100644
--- a/tools/perf/benchmarks/memory.py
+++ b/tools/perf/benchmarks/memory.py
@@ -4,30 +4,27 @@
 from telemetry import test
 
 from measurements import memory
-from page_sets import mobile_memory
-from page_sets import top_25
-from page_sets import top_desktop_sites_2012Q3
-from page_sets import tough_dom_memory_cases
+import page_sets
 
 
 @test.Disabled('android')  # crbug.com/370977
 class MemoryMobile(test.Test):
   test = memory.Memory
-  page_set = mobile_memory.MobileMemoryPageSet()
+  page_set = page_sets.MobileMemoryPageSet
 
 
 class MemoryTop25(test.Test):
   test = memory.Memory
-  page_set = top_25.Top25PageSet()
+  page_set = page_sets.Top25PageSet
 
 
 class Reload2012Q3(test.Test):
   tag = 'reload'
   test = memory.Memory
-  page_set = top_desktop_sites_2012Q3.Top2012Q3PageSet()
+  page_set = page_sets.Top2012Q3PageSet
 
 
 @test.Disabled('android')  # crbug.com/371153
 class MemoryToughDomMemoryCases(test.Test):
   test = memory.Memory
-  page_set = tough_dom_memory_cases.ToughDomMemoryCasesPageSet()
+  page_set = page_sets.ToughDomMemoryCasesPageSet