Added support for improvement_direction to relevant values, which is propogated to chartjson.

tools/telemetry/telemetry/value/skip.py

Index: tools/telemetry/telemetry/value/skip.py
diff --git a/tools/telemetry/telemetry/value/skip.py b/tools/telemetry/telemetry/value/skip.py
index 2b03725e1cf0fad17e5e35d72a39beb34c4e4fcd..fe3a95063d31b5894086a0a223a8ef2ee26cf9f9 100644
--- a/tools/telemetry/telemetry/value/skip.py
+++ b/tools/telemetry/telemetry/value/skip.py
@@ -54,8 +54,9 @@ class SkipValue(value_module.Value):
     kwargs = value_module.Value.GetConstructorKwArgs(value_dict, page_dict)
     del kwargs['name']
     del kwargs['units']
-    important = kwargs.get('important', None)
-    if important != None:
+    if 'higher_is_better' in kwargs:
+      del kwargs['higher_is_better']
+    if 'important' in kwargs:
       del kwargs['important']
     kwargs['reason'] = value_dict['reason']