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

tools/telemetry/telemetry/value/string.py

Index: tools/telemetry/telemetry/value/string.py
diff --git a/tools/telemetry/telemetry/value/string.py b/tools/telemetry/telemetry/value/string.py
index b1cb6ff45eda72cd47b7d460e9b4d089e5c31b24..6628a1b38a1d315451e2ce1c8aed26bc9e326184 100644
--- a/tools/telemetry/telemetry/value/string.py
+++ b/tools/telemetry/telemetry/value/string.py
@@ -16,7 +16,8 @@ class StringValue(value_module.Value):
     string value:
        StringValue(page, 'page_hash', 'hash', '74E377FF')
     """
-    super(StringValue, self).__init__(page, name, units, important, description)
+    super(StringValue, self).__init__(
+        page, name, units, important, description)
     assert value is None or isinstance(value, basestring)
     none_values.ValidateNoneValueReason(value, none_value_reason)
     self.value = value
@@ -27,7 +28,7 @@ class StringValue(value_module.Value):
       page_name = self.page.url
     else:
       page_name = None
-    return 'StringValue(%s, %s, %s, %s, important=%s, description=%s)' % (
+    return ('StringValue(%s, %s, %s, %s, important=%s, description=%s)') % (
       page_name,
       self.name,
       self.units,
@@ -91,6 +92,7 @@ class StringValue(value_module.Value):
   @classmethod
   def _MergeLikeValues(cls, values, page, name):
     v0 = values[0]
+    print v0
     merged_value = [v.value for v in values]
     none_value_reason = None
     if None in merged_value: