Revert of Explicitly call SequenceToken's default constructor.

base/sequence_token_unittest.cc

Index: base/sequence_token_unittest.cc
diff --git a/base/sequence_token_unittest.cc b/base/sequence_token_unittest.cc
index ff8725e02f330c1508e03600075be134f75123fd..9cbf6747be8e114628c631b686fda7b5e453ab3e 100644
--- a/base/sequence_token_unittest.cc
+++ b/base/sequence_token_unittest.cc
@@ -14,8 +14,8 @@
 }
 
 TEST(SequenceTokenTest, OperatorEquals) {
-  SequenceToken invalid_a;
-  SequenceToken invalid_b;
+  const SequenceToken invalid_a;
+  const SequenceToken invalid_b;
   const SequenceToken valid_a = SequenceToken::Create();
   const SequenceToken valid_b = SequenceToken::Create();
 
@@ -31,8 +31,8 @@
 }
 
 TEST(SequenceTokenTest, OperatorNotEquals) {
-  SequenceToken invalid_a;
-  SequenceToken invalid_b;
+  const SequenceToken invalid_a;
+  const SequenceToken invalid_b;
   const SequenceToken valid_a = SequenceToken::Create();
   const SequenceToken valid_b = SequenceToken::Create();