Revert "Add multi results in legacy perf dashboard script."

This reverts commit 3ca3fb27.

Reason for revert:
Seems to be the incorrect way to handle multi-results. Instead of
returning an array of values, we should compute the average and return
a standard deviation as the last result.

https://chromeperf.appspot.com/report?sid=3b11bf2aa2cf2281472588fed4dfc1e0a9f514ff10bd9db09cb208c5306ac3c9

Original change's description:
> Add multi results in legacy perf dashboard script.
> 
> Currently when the script reads multiple results it outputs the
> last value read as well as a zero placehold for standard deviation.
> 
> According to benjhayden@ we can return all results in an array.
> This change does just that and adds a test. It also updates the
> expected unit test output.
> 
> Bug: 900677
> Change-Id: Icc38808ea83caddbdf6b8582e2ddc34db4f8cdf0
> Reviewed-on: https://chromium-review.googlesource.com/c/1338468
> Reviewed-by: Ned Nguyen <nednguyen@google.com>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#608882}

TBR=jmadill@chromium.org,benjhayden@chromium.org,nednguyen@google.com,eyaich@chromium.org

Change-Id: I24fe0fae6607bf4d1bf8fb55d2c4f78d18a74b71
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 900677
Reviewed-on: https://chromium-review.googlesource.com/c/1341087Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609076}

tools/perf/generate_legacy_perf_dashboard_json.py

@@ -73,9 +73,15 @@ class LegacyResultsProcessor(object):
 
     def __init__(self):
       self.important = False
-      self.values = []
+      self.value = 0.0
       self.stddev = 0.0
 
+    def __str__(self):
+      result = _FormatHumanReadable(self.value)
+      if self.stddev:
+        result += '+/-%s' % _FormatHumanReadable(self.stddev)
+      return result
+
   class Graph(object):
     """Encapsulates a set of points that should appear on the same graph."""
 
@@ -94,7 +100,7 @@ class LegacyResultsProcessor(object):
       """Returns a dictionary mapping trace names to [value, stddev]."""
       traces_dict = {}
       for name, trace in self.traces.items():
-        traces_dict[name] = trace.values
+        traces_dict[name] = [str(trace.value), str(trace.stddev)]
       return traces_dict
 
 
@@ -135,39 +141,37 @@ class LegacyResultsProcessor(object):
     graph = self._graphs.get(graph_name, self.Graph())
     graph.units = (match_dict['UNITS'] or '').strip()
     trace = graph.traces.get(trace_name, self.Trace())
-    value = match_dict['VALUE']
+    trace.value = match_dict['VALUE']
     trace.important = match_dict['IMPORTANT'] or False
 
     # Compute the mean and standard deviation for a list or a histogram,
     # or the numerical value of a scalar value.
-    if value.startswith('['):
+    if trace.value.startswith('['):
       try:
-        value_list = [float(x) for x in value.strip('[],').split(',')]
+        value_list = [float(x) for x in trace.value.strip('[],').split(',')]
       except ValueError:
         # Report, but ignore, corrupted data lines. (Lines that are so badly
         # broken that they don't even match the RESULTS_REGEX won't be
         # detected.)
-        logging.warning("Bad test output: '%s'" % value.strip())
+        logging.warning("Bad test output: '%s'" % trace.value.strip())
         return
-      value, trace.stddev, filedata = self._CalculateStatistics(
+      trace.value, trace.stddev, filedata = self._CalculateStatistics(
           value_list, trace_name)
       assert filedata is not None
       for filename in filedata:
         self._PrependLog(filename, filedata[filename])
-      trace.values += value_list
-    elif value.startswith('{'):
-      stripped = value.strip('{},')
+    elif trace.value.startswith('{'):
+      stripped = trace.value.strip('{},')
       try:
-        value, trace.stddev = [float(x) for x in stripped.split(',')]
+        trace.value, trace.stddev = [float(x) for x in stripped.split(',')]
       except ValueError:
-        logging.warning("Bad test output: '%s'" % value.strip())
+        logging.warning("Bad test output: '%s'" % trace.value.strip())
         return
-      trace.values.append(value)
     else:
       try:
-        trace.values.append(float(value))
+        trace.value = float(trace.value)
       except ValueError:
-        logging.warning("Bad test output: '%s'" % value.strip())
+        logging.warning("Bad test output: '%s'" % trace.value.strip())
         return
 
     graph.traces[trace_name] = trace

tools/perf/testdata/artificial_graph-summary.dat

-{"traces": {"trace_with_multiple_samples": [100.0, 200.0, 300.0, 400.0], "trace_with_one_sample": [177.0], "trace_with_one_sample_comma": [177.0], "trace_with_three_samples": [100.0, 120.0, 200.0], "trace_with_three_samples_comma": [100.0, 120.0, 200.0]}, "units": "you-nits"}
\ No newline at end of file
+{"traces": {"trace_with_one_sample": ["177.0", "0.0"], "trace_with_one_sample_comma": ["177.0", "0.0"], "trace_with_three_samples": ["140.0", "43.2049379894"], "trace_with_three_samples_comma": ["140.0", "43.2049379894"]}, "units": "you-nits"}

tools/perf/testdata/commit_charge-summary.dat

-{"important": ["12t_cc", "1t_cc", "1t_cc_ref", "5t_cc"], "traces": {"12t_cc": [50200.0], "1t_cc": [22536.0], "1t_cc_ref": [22536.0], "5t_cc": [49412.0]}, "units": "kb"}
\ No newline at end of file
+{"traces": {"12t_cc": ["50200.0", "0.0"], "1t_cc": ["22536.0", "0.0"], "1t_cc_ref": ["22536.0", "0.0"], "5t_cc": ["49412.0", "0.0"]}, "important": ["12t_cc", "1t_cc", "1t_cc_ref", "5t_cc"], "units": "kb"}

tools/perf/testdata/graphing_processor.log

@@ -47,10 +47,3 @@ RESULT artificial_graph: trace_with_one_sample= [177.0] you-nits
 RESULT artificial_graph: trace_with_one_sample_comma= [177.0,] you-nits
 RESULT artificial_graph: trace_with_three_samples= [100.0,120.0,200.0] you-nits
 RESULT artificial_graph: trace_with_three_samples_comma= [100.0,120.0,200.0,] you-nits
-
-# Artificial log output to test multiple results with the same name
-
-RESULT artificial_graph: trace_with_multiple_samples= 100 you-nits
-RESULT artificial_graph: trace_with_multiple_samples= 200 you-nits
-RESULT artificial_graph: trace_with_multiple_samples= 300 you-nits
-RESULT artificial_graph: trace_with_multiple_samples= 400 you-nits

tools/perf/testdata/processes-summary.dat

-{"traces": {"12t_proc": [3.0], "1t_proc": [2.0], "1t_proc_ref": [1.0], "5t_proc": [3.0]}, "units": ""}
\ No newline at end of file
+{"traces": {"1t_proc": ["2.0", "0.0"], "1t_proc_ref": ["1.0", "0.0"], "12t_proc": ["3.0", "0.0"], "5t_proc": ["3.0", "0.0"]}, "units": ""}

tools/perf/testdata/vm_final_browser-summary.dat

-{"traces": {"12t_vm_b": [10556.0], "1t_vm_b": [8712.0], "1t_vm_b_ref": [5712.0], "5t_vm_b": [10404.0]}, "units": "kb"}
\ No newline at end of file
+{"traces": {"1t_vm_b": ["8712.0", "0.0"], "1t_vm_b_ref": ["5712.0", "0.0"], "12t_vm_b": ["10556.0", "0.0"], "5t_vm_b": ["10404.0", "0.0"]}, "units": "kb"}

tools/perf/testdata/vm_final_total-summary.dat

-{"traces": {"12t_vm": [55740.0], "1t_vm": [29696.0], "1t_vm_ref": [9696.0], "5t_vm": [54936.0]}, "units": "kb"}
\ No newline at end of file
+{"traces": {"1t_vm": ["29696.0", "0.0"], "1t_vm_ref": ["9696.0", "0.0"], "12t_vm": ["55740.0", "0.0"], "5t_vm": ["54936.0", "0.0"]}, "units": "kb"}

tools/perf/testdata/ws_final_browser-summary.dat

-{"traces": {"12t_ws_b": [18612.0], "1t_ws_b": [16892.0], "1t_ws_b_ref": [26892.0], "5t_ws_b": [18504.0]}, "units": "kb"}
\ No newline at end of file
+{"traces": {"1t_ws_b": ["16892.0", "0.0"], "1t_ws_b_ref": ["26892.0", "0.0"], "12t_ws_b": ["18612.0", "0.0"], "5t_ws_b": ["18504.0", "0.0"]}, "units": "kb"}

tools/perf/testdata/ws_final_total-summary.dat

-{"important": ["12t_ws", "1t_ws", "1t_ws_ref", "5t_ws"], "traces": {"12t_ws": [63984.0], "1t_ws": [41960.0], "1t_ws_ref": [41960.0], "5t_ws": [63276.0]}, "units": "kb"}
\ No newline at end of file
+{"traces": {"12t_ws": ["63984.0", "0.0"], "1t_ws": ["41960.0", "0.0"], "1t_ws_ref": ["41960.0", "0.0"], "5t_ws": ["63276.0", "0.0"]}, "important": ["12t_ws", "1t_ws", "1t_ws_ref", "5t_ws"], "units": "kb"}