TrigGenericMonitoringTool: copy defineHistogram from AthenaMonitoring

TrigGenericMonitoringTool is deprecated and is only kept in master as
long as we need to keep running the Run-2 trigger. As such it is better
that it contains its own copy of `defineHistogram`. That way we can
freely modify the new version in AthenaMonitoring and don't have to
worry about backwards compatibility.

Trigger/TrigMonitoring/TrigMonitorBase/python/TrigGenericMonitoringToolConfig.py

-# Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
 
 from AthenaCommon.Logging import logging
 log = logging.getLogger('TrigGenericMonitoringToolConfig.py')
@@ -19,8 +19,42 @@ else:
         as TrigGenericMonitoringTool
     log.info("Using thread-safe TrigGenericMonitoringTool")
 
-from AthenaMonitoring.GenericMonitoringTool import defineHistogram as __defineHistogram
-defineHistogram = __defineHistogram
+
+## Generate histogram definition string for the `TrigGenericMonitoringTool.Histograms` property
+#
+#  For full details see the TrigGenericMonitoringTool documentation.
+#  @param varname  one (1D) or two (2D) variable names separated by comma
+#  @param type     histogram type
+#  @param path     top-level histrogram directory
+#  @param title    Histogram title and optional axis title (same syntax as in TH constructor)
+#  @param opt      Histrogram options (see TrigGenericMonitoringTool)
+#  @param labels   List of bin labels (for a 2D histogram, sequential list of x- and y-axis labels)
+def defineHistogram(varname, type='TH1F', path='EXPERT',
+                    title=None,
+                    xbins=100, xmin=0, xmax=1,
+                    ybins=None, ymin=None, ymax=None, zmin=None, zmax=None, opt='', labels=None):
+
+    if title is None: title=varname
+    coded = "%s, %s, %s, %s, %d, %f, %f" % (path, type, varname, title, xbins, xmin, xmax)
+    if ybins is not None:
+        coded += ",%d, %f, %f" % (ybins, ymin, ymax)
+        if zmin is not None:
+            coded += ", %f, %f" % (zmin, zmax)
+    if ybins is None and ymin is not None:
+        coded += ", %f, %f" % (ymin, ymax)
+
+    if isinstance(labels, list) and len(labels)>0:
+        coded += ',' + ':'.join(labels) + ':'
+
+    # For backwards compatibility
+    elif labels is not None:
+        labels = labels.strip()   # remove spurious white-spaces
+        if len(labels)>0:
+            if labels[-1]!=':': labels += ':'  # C++ parser expects at least one ":"
+            coded += ",%s " % labels
+    coded += ", %s" % opt
+
+    return coded
 
 
 class TrigGenericMonitoringToolConfig(TrigGenericMonitoringTool):