Update oldest supported browser versions in feature_matrix.py. NFC

These were out of sync with settings.js for some reason.

Author: sbc100

tools/feature_matrix.py

@@ -15,12 +15,12 @@
 
 UNSUPPORTED = 0x7FFFFFFF
 
-# Oldest support browser versions.  These have been set somewhat
-# arbitrarily for now.
+# Oldest support browser versions.  Keep in sync with
+# src/settings.js.
 # TODO(sbc): Design a of policy for managing these values.
-OLDEST_SUPPORTED_CHROME = 45  # September 1, 2015
-OLDEST_SUPPORTED_FIREFOX = 40  # August 11, 2015
-OLDEST_SUPPORTED_SAFARI = 101000  # September 20, 2016
+OLDEST_SUPPORTED_CHROME = 33  # 2014-02-18.
+OLDEST_SUPPORTED_FIREFOX = 34  # 2014-12-01
+OLDEST_SUPPORTED_SAFARI = 90000  # 2015
 # 10.19.0 is the oldest version of node that we do any testing with.
 # Keep this in sync with the test-node-compat in .circleci/config.yml.
 OLDEST_SUPPORTED_NODE = 101900