Remove memory metrics from WebRTC measurements.

We need to rewrite to tbm2 in order to get memory. We don't really look
at memory metrics anyway at this point, so remove for now.

BUG=632295
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.perf:android_s5_perf_cq;master.tryserver.chromium.perf:linux_perf_cq;master.tryserver.chromium.perf:mac_retina_perf_cq;master.tryserver.chromium.perf:winx64_10_perf_cq

Review-Url: https://codereview.chromium.org/2325153002
Cr-Commit-Position: refs/heads/master@{#417603}

tools/perf/measurements/webrtc.py

@@ -6,7 +6,6 @@ from telemetry.page import legacy_page_test
 
 from metrics import cpu
 from metrics import media
-from metrics import memory
 from metrics import power
 from metrics import webrtc_stats
 
@@ -18,7 +17,6 @@ class WebRTC(legacy_page_test.LegacyPageTest):
     super(WebRTC, self).__init__()
     self._cpu_metric = None
     self._media_metric = None
-    self._memory_metric = None
     self._power_metric = None
     self._webrtc_stats_metric = None
 
@@ -27,19 +25,16 @@ class WebRTC(legacy_page_test.LegacyPageTest):
 
   def DidStartBrowser(self, browser):
     self._cpu_metric = cpu.CpuMetric(browser)
-    self._memory_metric = memory.MemoryMetric(browser)
     self._webrtc_stats_metric = webrtc_stats.WebRtcStatisticsMetric()
 
   def DidNavigateToPage(self, page, tab):
     self._cpu_metric.Start(page, tab)
     self._media_metric = media.MediaMetric(tab)
     self._media_metric.Start(page, tab)
-    self._memory_metric.Start(page, tab)
     self._power_metric.Start(page, tab)
     self._webrtc_stats_metric.Start(page, tab)
 
   def CustomizeBrowserOptions(self, options):
-    memory.MemoryMetric.CustomizeBrowserOptions(options)
     options.AppendExtraBrowserArgs('--use-fake-device-for-media-stream')
     options.AppendExtraBrowserArgs('--use-fake-ui-for-media-stream')
     power.PowerMetric.CustomizeBrowserOptions(options)
@@ -55,9 +50,6 @@ class WebRTC(legacy_page_test.LegacyPageTest):
     self._media_metric.Stop(page, tab)
     self._media_metric.AddResults(tab, results, exclude_metrics=exclude_metrics)
 
-    self._memory_metric.Stop(page, tab)
-    self._memory_metric.AddResults(tab, results)
-
     self._power_metric.Stop(page, tab)
     self._power_metric.AddResults(tab, results)