Merge all logic in PageMeasurementResults to PageTestResults.

tools/perf/metrics/test_page_measurement_results.py

 # Copyright 2014 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 telemetry.page import page as page_module
 from telemetry.results import page_measurement_results
 from telemetry.value import scalar
 
 
 class TestPageMeasurementResults(
     page_measurement_results.PageMeasurementResults):
   def __init__(self, test):
     super(TestPageMeasurementResults, self).__init__()
     self.test = test
     page = page_module.Page("http://www.google.com", {})
-    self.WillMeasurePage(page)
+    self.StartTest(page)
 
   def GetPageSpecificValueNamed(self, name):
     values = [value for value in self.all_page_specific_values
          if value.name == name]
     assert len(values) == 1, 'Could not find value named %s' % name
     return values[0]
 
   def AssertHasPageSpecificScalarValue(self, name, units, expected_value):
     value = self.GetPageSpecificValueNamed(name)
     self.test.assertEquals(units, value.units)
     self.test.assertTrue(isinstance(value, scalar.ScalarValue))
     self.test.assertEquals(expected_value, value.value)
 
   def __str__(self):
     return '\n'.join([repr(x) for x in self.all_page_specific_values])