Turn on eslint rule one-var and fix existing errors.

tracing/tracing/base/running_statistics_test.html

Index: tracing/tracing/base/running_statistics_test.html
diff --git a/tracing/tracing/base/running_statistics_test.html b/tracing/tracing/base/running_statistics_test.html
index ab27bafc089b66f9dacee6b38386fc24963a8bfd..49ea67d798c0bb6cd71ce11fa862bc0eac7f4d70 100644
--- a/tracing/tracing/base/running_statistics_test.html
+++ b/tracing/tracing/base/running_statistics_test.html
@@ -116,12 +116,10 @@ tr.b.unittest.testSuite(function() {
   });
 
   test('merge', function() {
-    var data1, data2, data, stats;
-
-    data1 = [];
-    data2 = [];
-    data = data1.concat(data2);
-    stats = run(data1).merge(run(data2));
+    var data1 = [];
+    var data2 = [];
+    var data = data1.concat(data2);
+    var stats = run(data1).merge(run(data2));
     assert.equal(Statistics.sum(data), stats.sum);
     assert.equal(Statistics.min(data), stats.min);
     assert.equal(Statistics.max(data), stats.max);