Simplify test file used by testBlinkPerfTracingMetricsForMeasureFrameTime & enable it on Android

This test was failing on Android Nexus 5 device due to the loading taking
too long. Simplifying its test case seems to fix the problem.

BUG=715685
TBR=wangxianzhu@chromium.org

Review-Url: https://codereview.chromium.org/2849153002
Cr-Commit-Position: refs/heads/master@{#468314}

third_party/WebKit/PerformanceTests/TestData/color-changes-measure-frame-time.html

@@ -25,7 +25,7 @@ function buildTree(parent, depth, arity, tagNameCallback, createElementCallback)
 
 // Build a tall tree that is skinny. A middle layer of
 // the tree should have the changeColor class.
-buildTree(document.body, 15, 2,
+buildTree(document.body, 5, 5,
   function(depth) {
     // Use divs at upper levels to avoid too much layout time.
     return depth > 9 ? 'div' : 'span';
@@ -37,20 +37,6 @@ buildTree(document.body, 15, 2,
   }
 );
 
-// Build a short tree that is fat. A middle layer of
-// the tree should have the changeColor class.
-buildTree(document.body, 6, 7,
-  function(depth) {
-    // Use divs at upper levels to avoid too much layout time.
-    return depth > 4 ? 'div' : 'span';
-  },
-  function(element, depth) {
-    element.style.backgroundColor = 'orange';
-    if (depth == 3)
-      element.setAttribute('class', 'changeColor');
-  }
-);
-
 var runCount = 0;
 var elementsToChange = document.getElementsByClassName('changeColor');
 var colors = [

tools/perf/benchmarks/blink_perf_unittest.py

@@ -4,7 +4,6 @@
 import os
 import unittest
 
-from telemetry import decorators
 from telemetry import story
 from telemetry.page import page as page_module
 from telemetry.testing import options_for_unittests
@@ -56,7 +55,6 @@ class BlinkPerfTest(page_test_test_case.PageTestTestCase):
     self.assertEquals(len(update_layout_trees), 1)
     self.assertGreater(update_layout_trees[0].GetRepresentativeNumber, 0.1)
 
-  @decorators.Disabled('android')  # crbug.com/715685
   def testBlinkPerfTracingMetricsForMeasureFrameTime(self):
     results = self.RunMeasurement(measurement=self._measurement,
         ps=self._CreateStorySetForTestFile(