Move AddValue/AddSummaryValue to PageTestResults.

tools/telemetry/telemetry/results/gtest_test_results.py

Index: tools/telemetry/telemetry/results/gtest_test_results.py
diff --git a/tools/telemetry/telemetry/results/gtest_test_results.py b/tools/telemetry/telemetry/results/gtest_test_results.py
index d88519cff9b810f536d20b35272a19b4373d3211..3153556ef67399d4b0afdf52dbbf9188d531d1ea 100644
--- a/tools/telemetry/telemetry/results/gtest_test_results.py
+++ b/tools/telemetry/telemetry/results/gtest_test_results.py
@@ -22,6 +22,11 @@ class GTestTestResults(page_test_results.PageTestResults):
         '(%0.f ms)' % self._GetMs())
     self._output_stream.flush()
 
+  def ValidateValue(self, value):
+    # TODO(chrishenry): When FailureValue is added, this should instead
+    # validate that isinstance(value, FailureValue) is true.
+    raise Exception('GTestTestResults does not support AddValue().')
+
   def AddFailure(self, page, err):
     super(GTestTestResults, self).AddFailure(page, err)
     self._emitFailure(page, err)