Revert of Use an explicit identifier in Config

webrtc/test/common_unittest.cc

Index: webrtc/test/common_unittest.cc
diff --git a/webrtc/test/common_unittest.cc b/webrtc/test/common_unittest.cc
index a239dade73fdadebfcece97614805d6003869d5f..082c18c2c7d9361fde111a1880e078bbf050edb7 100644
--- a/webrtc/test/common_unittest.cc
+++ b/webrtc/test/common_unittest.cc
@@ -15,7 +15,6 @@
 namespace {
 
 struct MyExperiment {
-  static const ConfigOptionID identifier = ConfigOptionID::kMyExperimentForTest;
   static const int kDefaultFactor;
   static const int kDefaultOffset;
 
@@ -57,8 +56,6 @@
 }
 
 struct Algo1_CostFunction {
-  static const ConfigOptionID identifier =
-      ConfigOptionID::kAlgo1CostFunctionForTest;
   Algo1_CostFunction() {}
 
   virtual int cost(int x) const {