Roll infra_libs and gae_ts_mon in luci-py, and add field_specs to all metrics

client/third_party/infra_libs/ts_mon/common/errors.py

Index: client/third_party/infra_libs/ts_mon/common/errors.py
diff --git a/client/third_party/infra_libs/ts_mon/common/errors.py b/client/third_party/infra_libs/ts_mon/common/errors.py
index 0784a579791600fad4a816389a870d0f9510f947..3bf76315ce16340f840863e648bf96def7834b99 100644
--- a/client/third_party/infra_libs/ts_mon/common/errors.py
+++ b/client/third_party/infra_libs/ts_mon/common/errors.py
@@ -125,3 +125,20 @@ class UnknownModificationTypeError(MonitoringError):
 
   def __str__(self):
     return 'Unknown modification type "%s"' % self.mod_type
+
+
+class MetricDefinitionError(MonitoringError):
+  """Raised when a metric was defined incorrectly."""
+
+
+class WrongFieldsError(MonitoringError):
+  """Raised when a metric is given different fields to its definition."""
+
+  def __init__(self, metric_name, got, expected):
+    self.metric_name = metric_name
+    self.got = got
+    self.expected = expected
+
+  def __str__(self):
+    return 'Metric "%s" is defined with %s fields but was given %s' % (
+        self.metric_name, self.expected, self.got)