[Telemetry] Fix histogram naming.

trace_tags should show up on the trace names but not the chart names. Previously
we'd output:
HISTOGRAM V8.MemoryHeapSampleTotalUsed_foo: V8.MemoryHeapSampleTotalUsed_foo=

Now we output:
HISTOGRAM V8.MemoryHeapSampleTotalUsed: V8.MemoryHeapSampleTotalUsed_foo=

This prevents an explosion of charts as seen on:
http://build.chromium.org/f/chromium/perf/linux-release/moz/report.html?history=150&rev=-1&graph=V8.MemoryExternalFragmentationTotal_extcs1_0.5

BUG=196411
TEST=tools/perf/run_multipage_benchmarks --browser=system page_cycler tools/perf/page_sets/page_cycler/moz.json --output-trace-tag=_foo
NOTRY=True


Review URL: https://chromiumcodereview.appspot.com/12900005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@189022 0039d316-1c4b-4281-b951-d872f2087c98

build/android/pylib/perf_tests_helper.py

@@ -110,11 +110,10 @@ def PrintPerfResult(measurement, trace, values, units, result_type='default',
     # across different histograms.
     assert len(values) == 1
     value = values[0]
-    measurement += '.' + trace_name
     output = '%s%s: %s= %s' % (
         RESULT_TYPES[result_type],
         _EscapePerfResult(measurement),
-        _EscapePerfResult(measurement),
+        trace_name,
         value)
     avg, sd = GeomMeanAndStdDevFromHistogram(value)
 

tools/telemetry/telemetry/page/page_benchmark_results.py

@@ -134,7 +134,7 @@ class PageBenchmarkResults(page_test.PageTestResults):
         by_url_data_type = 'unimportant-histogram'
       else:
         by_url_data_type = 'unimportant'
-      if '.' in measurement:
+      if '.' in measurement and 'histogram' not in data_type:
         measurement, trace = measurement.split('.', 1)
         trace += (trace_tag or '')
       else: