Add Value FromDict to Telemetry

tools/telemetry/telemetry/value/failure.py

Index: tools/telemetry/telemetry/value/failure.py
diff --git a/tools/telemetry/telemetry/value/failure.py b/tools/telemetry/telemetry/value/failure.py
index 252bb22f2c454e087d301513bdf611b39adc7aea..ba6998ad4b4c6c22c0c18f03ae2fb6b11c1f4779 100644
--- a/tools/telemetry/telemetry/value/failure.py
+++ b/tools/telemetry/telemetry/value/failure.py
@@ -29,10 +29,15 @@ class FailureValue(value_module.Value):
       page: The page where this failure occurs.
       message: A string message describing the failure.
     """
+    exc_info = cls._GetExcInfoFromMessage(message)
+    return FailureValue(page, exc_info)
+
+  @staticmethod
+  def _GetExcInfoFromMessage(message):
     try:
       raise Exception(message)
     except Exception:
-      return FailureValue(page, sys.exc_info())
+      return sys.exc_info()
 
   def __repr__(self):
     if self.page:
@@ -61,8 +66,8 @@ class FailureValue(value_module.Value):
   def GetRepresentativeString(self):
     return None
 
-  @classmethod
-  def GetJSONTypeName(cls):
+  @staticmethod
+  def GetJSONTypeName():
     return 'failure'
 
   def AsDict(self):
@@ -70,6 +75,19 @@ class FailureValue(value_module.Value):
     d['value'] = GetStringFromExcInfo(self.exc_info)
     return d
 
+  @staticmethod
+  def FromDict(value_dict, page_dict):
+    kwargs = value_module.Value.GetConstructorKwArgs(value_dict, page_dict)
+    del kwargs['name']
+    del kwargs['units']
+    important = kwargs.get('important', None)
+    if important != None:
+      del kwargs['important']
+    kwargs['exc_info'] = FailureValue._GetExcInfoFromMessage(
+        value_dict['value'])
+
+    return FailureValue(**kwargs)
+
   @classmethod
   def MergeLikeValuesFromSamePage(cls, values):
     assert False, 'Should not be called.'