| # Copyright 2013 The Chromium Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| from metrics import histogram_util |
| |
| BROWSER_HISTOGRAM = 'browser_histogram' |
| RENDERER_HISTOGRAM = 'renderer_histogram' |
| |
| class HistogramMetric(object): |
| def __init__(self, histogram, histogram_type): |
| self.name = histogram['name'] |
| self.units = histogram['units'] |
| self.histogram_type = histogram_type |
| self._start_values = dict() |
| |
| def Start(self, page, tab): |
| """Get the starting value for the histogram. This value will then be |
| subtracted from the actual measurement.""" |
| data = self._GetHistogramFromDomAutomation(tab) |
| if data: |
| self._start_values[page.url + self.name] = data |
| |
| def GetValue(self, page, tab, results): |
| data = self._GetHistogramFromDomAutomation(tab) |
| if not data: |
| return |
| new_histogram = histogram_util.SubtractHistogram( |
| data, self._start_values[page.url + self.name]) |
| results.Add(self.name, self.units, new_histogram, |
| data_type='unimportant-histogram') |
| |
| @property |
| def histogram_function(self): |
| if self.histogram_type == BROWSER_HISTOGRAM: |
| return 'getBrowserHistogram' |
| return 'getHistogram' |
| |
| def _GetHistogramFromDomAutomation(self, tab): |
| return histogram_util.GetHistogramFromDomAutomation( |
| self.histogram_function, self.name, tab) |
