Move memory-related histogram data collection to metrics/memory.py

tools/perf/measurements/startup_warm.py

Index: tools/perf/measurements/startup_warm.py
diff --git a/tools/perf/measurements/startup_warm.py b/tools/perf/measurements/startup_warm.py
index 7c346b5c50e2d34323210a7dc3b14410f25b1fe0..967e319b428bad20e4590106b09f1de36fe044b7 100644
--- a/tools/perf/measurements/startup_warm.py
+++ b/tools/perf/measurements/startup_warm.py
@@ -4,17 +4,18 @@
 
 import json
 
+from metrics import histogram
 from telemetry.page import page_measurement
 
-
-class StartupWarm(page_measurement.PageMeasurement):
-  """Test how long Chrome takes to load when warm."""
-  HISTOGRAMS_TO_RECORD = {
+_HISTOGRAMS = {
     'messageloop_start_time' :
-        'Startup.BrowserMessageLoopStartTimeFromMainEntry',
+          'Startup.BrowserMessageLoopStartTimeFromMainEntry',
     'window_display_time' : 'Startup.BrowserWindowDisplay',
     'open_tabs_time' : 'Startup.BrowserOpenTabs'}
 
+class StartupWarm(page_measurement.PageMeasurement):
+  """Test how long Chrome takes to load when warm."""
+
   def __init__(self):
     super(StartupWarm, self).__init__(needs_browser_restart_after_each_run=True,
                                       discard_first_result=True)
@@ -28,25 +29,17 @@ class StartupWarm(page_measurement.PageMeasurement):
           '--reduce-security-for-dom-automation-tests')
 
   def MeasurePage(self, page, tab, results):
-    # TODO(jeremy): Remove references to
-    # domAutomationController.getBrowserHistogram when we update the reference
-    # builds.
-    get_histogram_js = ('(window.statsCollectionController ?'
-        'statsCollectionController :'
-        'domAutomationController).getBrowserHistogram("%s")')
-
-
-    for display_name, histogram_name in self.HISTOGRAMS_TO_RECORD.iteritems():
-      result = tab.EvaluateJavaScript(get_histogram_js % histogram_name)
-      result = json.loads(result)
+    for display_name, histogram_name in _HISTOGRAMS.iteritems():
+      histogram_data = json.loads(histogram.GetHistogramData(
+          histogram.BROWSER_HISTOGRAM, histogram_name, tab))
       measured_time = 0
 
-      if 'sum' in result:
+      if 'sum' in histogram:
         # For all the histograms logged here, there's a single entry so sum
         # is the exact value for that entry.
-        measured_time = result['sum']
-      elif 'buckets' in result:
-        measured_time = \
-            (result['buckets'][0]['high'] + result['buckets'][0]['low']) / 2
+        measured_time = histogram_data['sum']
+      elif 'buckets' in histogram_data:
+        measured_time = ((histogram_data['buckets'][0]['high'] +
+                         histogram_data['buckets'][0]['low']) / 2)
 
       results.Add(display_name, 'ms', measured_time)